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Kilobaud 1978-06 pages 001-049 Medium

1. M OUTPT IN STATUS BYTE ANI 4 MASK BYTE JNZ OUTPT LOOP IF NOT READY MOV A M READY FOR DATA ANI 7FH ZERO PARITY BIT CMA BYTE OUT 0 SEND IT TO PORT 0 DCR B LOOP CNTR RZ RETURN IF DONE INX H GET NEXT CHAR IF NOT DONE JMP OUTPT INP IN STATUS 01 MASK JNZ INP IN 0 CMA ANI 7FH RET Table 1 machine code of 41 00 rather than the necessary 41 20 This can be rectified if a space follows the in the source of DW A It should read DW 5 My assembler didn t like the instructions given it on addresses 210 212 it would rather have seen SPACE DB 20 20 20 6 Similarly address 213 as sembles to OAOD rather than the necessary ODOA A source state ment fix of DW OAODH will straighten that out 7 As is necessary for most ma chines I had to rewrite the I O routines to conform with the Intel TTY interface card For those of you who have an Intellec 8 Mod 80 the routines are shown in Table 1 This program is an asset to any hobbyist or programmer who programs in 8080 assembly language Rick Beutnagel Hilton NY Score 2 For Consumer Computer In the March 1978 issue of Kilobaud a short article entitled Consumer Computer appeared This work describes software written in North Star BASIC capable of generating replie
2. Dm 7 Sooo 25 gt 5 gt 5 gt gt gt 5 44 5 uOEZOOeUZENZSOOW fied to reflect your high mem gt 29 Oo Guo 2 gr we 225 gt 5255 2225555522 9 lt ory limit in offset octal For ex 7 5 lt 5 le if tem h sca MES AE 3 at e e total of 8K of RAM the BEGIN ESSE 55 5 5 ue oi o 3 EQU statement would be EQU 76000 4 2 8 gt wa c r ab ard A 2 22 from Table 3 If you wish to use 5 an output port other than 700 pad ii 52 22522 2 52 6 the TTY EQU statement must REPRISE Ma m n TERASA MR be changed to the new port 8 qum 9442 5 co e number 27 69 48 8000 00 29 0 9 FU r PR 10 2 8 27 650 o 99 www wwowowwowowwowwowwowo woo Once you have defined the 222272 22222222222 229 2292029290909299 changes to be made to the ASCII Baudot driver the source code listing can be changed 48 Program A Assembly listing 3NI 1830 0 n MOYYV dN 8 132YM8 5 15 3583 3 8 13 2Y848 1431 dO OOCuju 9I 753x zzo0a0QO0uux22 23385 x lt 4 9 NYH 831 389 3 1vnb3 1 5531 77 cu ar uS I DQ 9
3. READ BEFORE PROCEEDING FURTHER GOSUB314 GOSUB318 INPUT WHAT IS YOUR AGE A A1 INT 6 220 A YOUR BEGINNING TRAINING PULSE RATE IS A1 BEATS PER MINUTE GOSUB314 GOSUB318 BEGIN WITH ONE MINUTE OF LIMB ERING EXERCISES SUCH AS 1 STRETCHING 2 TWISTING 3 BENDING EASY DOES IT LIMBER UP SLOWLY GOSUB314 GOSUB318 TAB 12 START FOR X 1T08 NEXT M 60 GOSUB264 TAB 10 ONE MINUTE GOSUB318 NEXT UP 15 4 MINUTES OF MUSCLE EXERCISES TO ADD MUSCLE TISSUE GOSUB314 15 PUSHAWAYS AND THEN 15 SITBACKS IN APPROXIMATELY THE NEXT TWO MINUTES THEN CHECK YOUR PULSE RATE GOSUB314 GOSUB318 10 55 M 120 GOSUB264 NOW LETS CHECK YOUR PULSE RATE GOSUB282 E E 700 LONG MULTIPLE ENTRIES WILL E alone Grounding of these lines produces an input different from 255 and the program drops into another loop You can momentarily ground one of the port one input lines by using a push button attached to a ten foot cord which allows you to move around during the pulse rate determination It is im portant not to stand perfectly still during this process Ac cording to the book passing out cold is a possible con sequence of remaining still immediately following exer cise and my computer s bag of tricks does not yet include administration of
4. A Left Bracket B Reverse Slant R Right Bracket B Up Arrow 7 0 Underline You can make arbitrary assign PU Uo ments by modifying the lookup table used in the driver program to convert ASCII characters generated in the computer to Baudot characters Hardware The ASCII Baudot driver was written for the Heath H8 com puter system This documenta tion assumes that the interface to the teleprinter will be made via an H8 2 parallel port Since Heath software makes no distinction between serial and parallel ports an H8 5 serial port can be used How ever you will normally have CRT console already con nected to a serial port with the second port on the board automatically committed to the c2 0 3 T 5 R4 3 TO LOOP o KEYING TRANSISTOR 5 93 4 8 2 1 0 35 21 NOTES A NC FOR 5 VOLT UARTS 12 VOLTS FOR ALL OTHERS SEE PARTS LIST 8 ALL RESISTORS 14 W 10 C ALL CAPACITORS IN uF D H amp 2 00 CONNECTIONS AT END OF H8 2 CABLE Fig 1 H8 2 to external UART interface H8 2 Interface Function Pin Data 0 Data 1 Data 2 Data 3 Data 4 Data 5 Data 6 Data 7 Ground Data Taken Take Data Device Cntrl Device Rdy Device Cntrl Send Data Data Sent Ground Data 7 Data 6 Data 5 Data 4 Data 3 Data 2 Data 1 Data 0 OOnN Of WN eh e cassette tape A second serial board
5. 4 lt 22 013 4 C4 012 gt C94 ot 4 e 246 C25 010 H E m xj 5 Ed el ZEE LH H AVA 111 Y 3 2 LN LN 872 Ai2 532 Al3 652 All 7 ALL RESISTORS 3002 2 ICs 1 74121 2 7474 3 5 8 7402 4 7437 6 22 7404 7 7408 74123 10 15 18 8 97 11 14 74193 19 21 74LS368 Miscellaneous 1 circuit board of choice 7 x 12 see text 1 edge connector for circuit board 24 LEDs MV5054 or similar 24 300 Ohm 4 W 10 resistors 10 330 Ohm W 10 resistors 18 2 2K Ohm 7 W 10 resistors 2 10K Ohm 4 W 5 resistors 1 20K Ohm 4 W 5 resistors 1 10 pF disk cap 1 0 01 uF disk cap 1 0 1 uF disk cap Switches 51 53 SPDT toggle switches 52 54 7 SPDT spring loaded toggle switches 550 15 SPDT toggle switches Parts list from the CPU stored in the location in 2 Set up address 0000 on sense switches SSO to 5515 and load this address by tog gling LOAD ADDRESS All ad dress LEDs should extinguish Remember all Z 80 programs must begin at zero on start up 3 Using 550 to 557 set up data byte 00111110 and enter this byte into location 0000 by toggling DEPOSIT The address LEDs should now indicate 0001 3E is the 2 80 op code for load accumulator immediate and its execution will cause the byte in location 0001 to be placed in the accu mulator register of the MPU 4 DEPOSIT 08 The ad dress should now read 0002 5 DE
6. 8259 O d jSSeuisng ay yseq ay 06 M aiemMyjoS siempleH Ppd a OA 7 A 27 22707 2 2 1 seop poqoN Emerson Brooks 517 Melody Lane Richardson TX 75081 Taming the I O Selectric Part 1 178 time to get that 1 0 Selectric you ve been using as a typewriter and interface it to your home computer Photo 1 The IBM Model 731 Selectric as used in the 1014 Remote Inquiry Unit The case has an extension on the bottom to house the solenoids which permit remote operation of the typewriter is no longer making the 1 Selectric and as more and more systems are upgraded there will be an increasing number of these units coming onto the surplus market I ve seen several articles on interfacing the Selectric but believe this is one of the best It s very likely the 1 Selectric will become more and more popular as a hard copy device for hobby systems due to its rugged construction no comparison with an Office Selectric and the cost 700 to 950 The Model 731 which Emerson s article is based on is mechanically the same as the Model 735 John L ast spring was just get ting started in the home computer hobby had as sembled my SWTPC M 6800 kit and was making my first attempt at programming when it became obvious that any serious work would re quire a hard copy output A
7. Note Tom Pittman now has an experimenter s manual avail able that explains many of these features and how to work with them They are not as sim ple as my approach The manual is available from Itty LET A A 1 PRINT Bitty Computers PO Box 23189 San Jose CA 95153 These are not significant handicaps if you re estimating the effect of several alter natives Round numbers are usually acceptable if you only want to get on base in some specific ball park cliches are fun once in a while Byte saving Tips Saving bytes of memory is a practical approach if your com puter has limited memory have 1250 bytes of free space now Let s talk about the memory saving part first Fig 1 is an example of a gram with no statement short cuts Fig 2 uses all the implied and abbreviated statements possible in this Tiny BASIC in terpreter Memory in Fig 1 is 492 bytes an average of 17 bytes per line while Fig 2 uses 410 bytes for an average of 14 bytes per line REM comments were added later and used 470 bytes Using implied statements causes the program to run NUMBER A IS 571 OWED IS O PRINT 5 ARE M PRINT LET N N 1 IF N20 THEN GOTO 170 PRINT PRINT DONE PRINT END 1 0 11 1 2 2 GOSUB 1 RUN 1226 AT 1 END PRINT THERE ARE I BYTES LEFT
8. big bucks are waiting It s Here Machine Language for the TRS 80 Radio Shack s T BUG Two Systems Sharing the Same Bus a look at distributed computing Computers in Classrooms Teaching the Teachers Publisher s Remarks 4 Editor s Remarks 7 Around the Industry 8 Books 11 New Products 14 Letters 18 Kilobaud Classified 112 Calendar 112 Corrections 112 Contest 117 READY for BUSINESS We ve got it all together the cost effectiveness and reliability of our 6800 computer system with a high capacity 1 2 megabyte floppy disk system PLUS an outstanding new DOS and file management system 1 MEGABYTE DISK SYSTEM 7 type controller and double sided disks give the DMAF1 introduces a new level of capability to system speed of data transfer unobtainable with small computer systems This disk system fea smaller drives tures two standard size floppy disk drives using OPERATING SYSTEM the new double sided disk and two heads per drive Usable storage space of over 600 kilobytes To compliment this outstanding hardware we per drive giving a total of over 1 0 megabyte of are supplying equally superior software The storage on line at all times Ideal for small busi disk operating system and Tile management Sys ness applications or for personal super sys tem is called FLEX It is one of the most flex ible and complete DOS s available for small sys tems tems but just as importa
9. was willing to use some low power Schottky packages was also willing to sacrifice the dynamic refresh capability of the Z 80 to take advantage of a straightforward method of front panel operation This method is called direct memory access DMA and is readily im plemented with the Z 80 MPU Dynamic memory could still be used but would require the use of an external refresh circuit My home brew is entirely stand alone with off line capability so did not care that DMA by other devices such as DMA requiring TVTs would not be possible during front panel operation This would not be a serious disadvantage consider ing the normal reason for using the front panel that is for small program development and or bootstrapping tape pro grams into memory With data latches and additional logic it would be possible to restore full operation Single step operation is a nice feature per mitting you to go through a pro gram op code by op code This is very handy for debugging software and fortunately very easily implemented Theory of Operation DMA is possible with a Tri state bus system and some means to suspend MPU opera tion On the Z 80 chip is a pin labeled BUSRQ It might better be named DMARQ because bringing this pin low forces the MPU to set its address data and Tri state output control signals to the third or high impedance state thereby facilitating DMA operation In our case switch
10. 236000 Table 3 Reconfiguring Heath programs Baudot machine prints 5 Reconfigured High Memory 11775 15871 19967 24063 28159 32255 36351 40447 information printed on the 4 ei d Baudot teleprinter e d 1 M c I S u 5 gt v j e Flowcharts for the driver are ace T oe _ E M 5343955 Se given in Fig 2 while the com 232 cap e ou wo a e oO uo ao cr eee uad ME ER 3 z 5 gt 2 2 522 255 9 552 printed by a model 28teleprint lt uf E pi em AER o 22 o scr ana uL 77 08 5522 Soo 8 229 program requires approximate 4222 A NE 2 32 220 Oo 0 a Zox 0 wae 4 27 ec 352 8 8 52 335 2 27945 driver easily mod 8357 522 TFT uu oc EM T e Uu ified to be compatible with your 62 4 SS 5 em CR Un o9 we S 2 2222 258525652 se 5 H8 system Program A will run 27 3822 o 8 ox lt z 90f a ab a e ee with 16K of RAM If your system 23u5 z care dps ut 43 5 f2Or2 404 differs from this the BEGIN sz 225 2o EQU statement must be modi 2 29 oe
11. Send for their catalog 128 South Taft Denver CO 80228 Isn t that a beauty The new Bytemaster from the Digital Group 2 80 based with either floppies DISKMON OS or Phi decks PHIMON They have a complete product catalog now PO Box 6528 Denver CO 80206 New York NY 10024 Kilobaud UL Corre 4 Cyr dee 4 7 amp LORAUD For those of you who haven t had the opportunity to meet our ex ecutive vice president Sherry Smythe then allow me to introduce her Her son Matt is on the far right and is one of the best booth managers the business Unfortunately we re going to have to do without his fine services for a couple of years while he goes down to Central America for some missionary work When it comes to quality S 100 systems you re going to have to look far and wide before you find something comparable to the Equinox 100 both electrically and mechanically There were three factors that accounted for the tremendous crowds around the Thinker Toys Parasitic Engineering booth George Morrow s new floppy interface board which can be configured for mini or standard sized drives the Equinox 100 and Lauren Kawakami Thinker Toys 1201 10th Berkeley 94710 Parasitic Engineer ing PO Box 6314 Albany CA 94706 39 There s Chuck Grant president of North Star Computers with his arm resting on one of their Horizon systems Keep your eyes open for a review of that system
12. THERE ARE 288 BYTES LEFT Fig 1 First program version using no shortcuts to write the program or save bytes This program uses 492 bytes exclusive of the REM statements REM statements use 470 bytes The short routine above illustrates how Tiny BASIC finds the number of bytes of free space remaining The user s manual tells how to do it 42 slower but the increase gram lines is worth the loss of speed if speed is your concern then Tiny BASIC may not be for you anyway Memory saving wasn t really necessary for this short program but in a 100 line program over 200 bytes could be saved 12 to 15 lines worth Such significant savings allow you to write longer programs The programs are still small but even a few more lines make them more useful And that s what we re trying to do Bytes could be saved in a few more places such as the spaces in the print input lines 130 through 160 but in the interest of clarity left them alone Decimal Values Calculations involving decimal numbers can be han dled several ways Anytime a percentage or a calculation resulting in a fraction occurs a decimal number results Dollars and cents are decimal numbers too Tiny BASIC trun cates decimal numbers down to the next lower whole num ber If the number is less than one the result is zero For this LIST reason accountants would probably not want to use Tiny BASIC Lines 130 through 180 are the input
13. You can keep the unit close at hand without its being in the way There s plenty of room for your terminal and a sliding keyboard shelf can put the keyboard within comfortable reach or out of the way when you re not using it The lower shelf fully handles the task of holding all the manuals that accompany a small microcomputer lab The Micro we anier _ Wintek s analog interface module desk is sturdily designed to last a long time under normal condi tions Computer Systems Design 1611 E Central Wichita KS 67214 Microprocessor Analog Interface Module The Wince Analog Interface Module makes it easy for labora tory and control engineers to in terface thermocouples and other transducers to a microprocessor It makes it equally easy to inter face the microprocessor to motors servos etc Options in clude a 16 channel multiplexer an 8 10 or 12 bit analog to digital converter and one or two 8 bit digital to analog converters The base price is 599 Other Wince Modules include the Con trol RAM ROM EROM Pro grammer CMOS RAM Battery Driver Sensor Console 1 Cassette Interface Wintek Corp 902 N 9th St Lafayette IN 47904 The Stringy Floppy The Exatron Stringy Floppy is a subsystem consisting of a con Exatron s Stringy Floppy 15 Central Data 2650 Computer System trol board connecting to the S 100 bus a small drive
14. an upcoming issue With the wide ranging use of North Star hardware and software these days suspect Chuck is quite pleased with what they ve done 1 would have asked him but he was too busy sell ing systems 2547 9th St Berkeley CA 94710 Who says the camera never lies In this photo Bob Mullen guess which one ap pears as a thoughtful contemplative handsome and debonair designer of the only S 100 logic probe extender board and relay opto isolator contro board on the market his partner Keith Britton appears to be awake Hey check into their new logic probe extender board Ilt uses 7 segment display and does the job nicely Mullen Computer Products Box 6214 Hayward CA 94545 40 Why is this man smiling Because he s Lou Frenzel director of computer market ing at Heath and he along with everyone else at Heath is tickled pink at the way their systems have taken off in sales Now their floppies are here and Heath s even happier can t tell you who that gentleman kneeling down eyeing their new floppy system is but his initials are Steve Jobs Drop a note to Heath and ask for their new catalog Heath Co Benton Harbor MI 49022 Becky Sallume of Vandenberg Data Prod ucts was one of the most lively hander outers at the Faire but this photo was taken at the end of the last day If you re in the market for a 16K S 100 board that runs cool then send VDP some of your hard earn
15. anyone to go into computer por traits The franchise fee will be not 7000 to 10 000 but only 5000 for everything including the computer line printer TV camera video monitor and soft ware We feel this system will have more capabilities than any other system available and we are dedicated to continually upgrading all units in the field so it will remain so Anyone desiring more information is invited to write me at Tri Mark Engineer ing 12402 W Kingsgate Knox ville TN 37922 Marshall Dudley President Sounds like a good topic for an article Marshall John Demystifying the April Tic Tac Toe Program I m sorry about the errors the Tic Tac Toe article appearing in the April Kilobaud Basically what happened is 1 I wrote the article before I had a printer and attempted to type the listings from my video 2 Kilobaud returned a draft of the article This draft contained numerous errors in the listing my fault and pages of program list ing were out of order Kilobaud placed page 10 in front of 9 3 The new proof was sent to me and we still had problems John Craig and decided to hold publication of the article until I obtained a computer generated listing 4 I sent computer listings writ ten in North Star BASIC since I no longer had Altair equipment This changed the article dras tically 5 We decided to go with cor rected versions of the typed list ing so as not to cha
16. departments about prospective microcomputer growth my software plans etc Hy took us off to the plant not far away where the TRS 80s are being made Wow Again no produc tion figures were to be let out of the bag but you can see from my pictures that the production is not insignificant They run the sys tems in for 24 hours so you know all the sets you can see are just a part of one day s production It was so difficult to tear myself and this is just one part and on If anyone tries to tell you Radio Shack isn t making a lot of 80s in Ft Worth tell him baloney away from the factory that we almost missed our plane back to Boston and home TRS 80 Is It Any Good I ve had letters from hundreds of TRS 80 owners and talked with dozens at the recent shows but I haven t had any negative comments yet on the system Oh everyone wants more memory and bigger BASIC but they are amazed at what the 80 can do with what it has and they are having a ball with it In view of this the recent blast in PCC at the 80 15 a mystery The people at Radio Shack were numbed by the negative review and as bewildered as I by it Yes the case for the keyboard and CPU is plastic but it is very attractive and it resists dings a lot better than metal and if you want to carry the system around the way most of us do you loudly hail the use of lightweight plastic instead of boat anchor iron
17. preter at the soft entry point The Tiny BASIC user s manual explains how to do this too A program does not have to be other at line 120 Whatever North Star Software Maillist Maillist is general purpose mailing label program capable of producing formatted lists for tractor fed or Xerox type labels Mailiist will also sort lists for any field Price 39 95 on diskette with manual stock to 14 day delivery in out driver Dos in out driver is designed to set up mapped memory video boards in conjunction with hard copy device The user may switch output under software control Any file directory may be listed while in BASIC without jumping to dos Spacebar will stop output for line by line listings Designed for use with S and any tv board Prce 12 95 on diskette with manual stock to 14 day delivery Register Register is a cash register and inventory control program The software will control a of sale terminal and printer It will search inventory for an item price and ticket it Register has provisions for min max automatic reorder and critical list Price 299 95 on diskette with manual Ail prices are FOB Santa Barbara Calitorma Terms COD Residents add 6 sales tax and 1 00 shipping Alpha Data Systems 267 Santa Barbara Ca 93102 805 682 5693 44 dividers engineering notation Datapoint CRT Terminals Fully Assembled Guaranteed 3360 9649 50 e Add
18. which latches the ad dress Then this address ap pears at the Q outputs and at the address bus via the buffers To increment an address already loaded toggle the EX ADDRESS _ LEOS SENSE SWITCHES AMINE NEXT switch 55 which is debounced and applied through 1 7 to pin 5 of IC11 Note that the increment does not occur until S5 is released This is because the 74193 counts up on zero to one tran sition which does not occur un til S5 is released Access to the data out bus is through buffers 17 and 18 These buffers are activated on ly during a write operation After the desired address is loaded the data is set by sense switches SSO to SS7 which do double duty as data and low order address byte switches With the data set the DEPOSIT switch S4 is activated If DMA has been granted to the front panel the debounced toggle passes through IC7b to 9 one shot The one shot places the data on the data out bus by enabling IC17 and 18 and trig gers the write pulse generator IC9b At the end of the data STEPPER SWITCH SINGLE STEP DEPOSIT EXAMINE NEXT Results of my efforts enable pulse from IC9a the ad dress counters are incre mented automatically to ac cess the next sequential loca tion The data in bus is con tinuously monitored by the in verter LED circuitry of IC6 and 22 Here 7404 types are used because there is little need to reduce loading on a bus
19. 12 13 14 15 16 17 18 24 21 20 GUARANTEE PRESET CASE TO LT RS OUTPUT CONSOLE INITIALIZATION 097 OF MODE INITIALIZE TTY USART Fig 2 Program flowcharts Function TBR1 TBR2 TBR3 TBR4 TBR5 TBR6 TBR7 TBR8 GND TRE TBRL CHARACTER OUT TO TTY CHOUT INITIALIZATION ACCUMULATOR in the same way as for an H10 Software The ASCII Baudot driver uses a lookup table to convert the ASCII character being sent to the system console to a Baudot character compatible with a five level teleprinter The routine is placed at the upper end of user RAM just below the stack where provisions have been included in Heath soft ware to allow user memory space The Heath software must be reconfigured to allow the ASCII Baudot driver to be used The changes include 1 redefining the high memory limit as de tailed in Table 3 2 changing five memory locations in each Heath program as shown in Table 4 Once the Heath software has been reconfigured the ASCII Baudot routine is loaded with the Heath program The ASCII Baudot driver need only be loaded once when going from one Heath reconfigured pro CASE AND CHARACTER TO PRINTER cco SYNTHESIZE LTRS F GS USING CARRY NEW CASE CMOUT RESTORE AF PRIN CHARACTER CMOUT 47 Examples LSB Li MSB 7 6 5 4 3 2 1 Assume A is the ASCII character Binary byte for A is 00001100 Octal equiv
20. Kilobaud Now let s do a recap of the hardware while referring to Photo 1 Going clockwise start ing on the left hand side of the table we have the TV camera sit ting on top of the terminal in cidentally you re going to need Photo 4 Larry Lowe layout draftsman and corporate pilot some floodlights aimed at the subject then we have a monitor for the video the SWTP system with the Digisector sitting on an extender board the right one minimum of 18K of main mem ory and last but not least the Malibu printer Add it up it s a heck of a lot less than anything you ve seen before The cost of the Digisector board includes the computer portrait software Photos 2 through 6 will intro duce you to the sharp team at Micro Works who put it all to gether and Fig 1 speaks for itself The Micro Works Malibu combination is a real winner By the way they have an 8080 S 100 version of the board in the works which will sell for about the same price Micro Works PO Box 1110 Del Mar CA 92014 Ph 714 756 2687 Photo 6 Bob McMann tech writer and senior tech nician 8080A 8085 Assembly Language Programming Lance A Leventhal Adam Osborne amp Associates Inc PO Box 2036 Berkeley CA 94702 7 50 400 Pages Assuming that there are other computer hobbyists who enjoy assembly language programming as much as I do I would like to pass on my thoughts about 8080 8085 Ass
21. NJ 08830 Digital Research has a new macroassembler and sym bolic instruction debugger both of which will be reviewed in an upcoming issue of Kilobaud Ver sion 1 4 of CP M is out too Drop them a line for more info PO Box 579 Pacific Grove CA 93950 Oliver Audio Engineering was looking good Beautiful booth and normally big crowds around it By the way did you know their new PROM programmer simply plugs into an existing PROM socket to do it s thing read program verify and duplicate Two models and they both sell for 295 OAE 676 West Wilson Ave Glendale CA 91203 If you re in the market for a low cost mass storage system then take a look at what the folks at Exatron have come up with It s not called a cassette it s a continuous loop tape wafer called the Stringy Floppy Each wafer holds 40K bytes and the transfer rate is an incredible 7200 kilobaud Loads a 4K program in about 5 seconds The system includes an S 100 controller board with 4K monitor assembler editor and the drive for 289 50 They also have a Tiny BASIC and a 5K BASIC available 1030 East Duane Ave Suite Sunnyvale 94086 Once again managed to chase off the crowds for a second to grab a shot of Dan Meyer presi dent of Southwest Technical Products sporting new beard They have a new disk system the DMAF1 for business applications that has a file management system called FLEX Oh the drives
22. Rf ea eg 27 wwe gt LI j Y Hey there he is The handsome and debonair Dr Lloyd Rice What can say That staid conservative gentleman on the leftis creator of famous Computalker Voice Synthesizer If you re in the the one and only Bill Godbout The mood of revelry was probably market give this one a listen before you buy Computalker Con due to the tremendous success of his Econoram memory boards sultants PO Box 1951 Dept K Santa Monica CA 90406 and all the other items in his catalog The smiling face in the center belongs to none other than Carl Warren the Senior Editor of Interface Age The gentleman on the right That s the real George Morrow Somebody who looks ike George posed for the ad on page 128 of the April Kilobaud but know it wasn t really him be cause George always wears tennis shoes and you d never catch him with a tie on Godbout Electronics Box 2355 Oakland Airport CA 94614 MINI r 24 y Cat gt 9 00 of the busiest booths at the Faire had to be Jade Computer Products man behind all the action is Don Smith shown the center photo with his better half Joanne One of the latest products to be added to their line is the REX personal computer shown in the left photo Don s adopted son Heath Kline president of Priority One Electronics 10031 Woodley Ave Sepulveda CA 91343 was sharing the booth and showing off his MiniScope and m
23. S3 Fig 1 is debounced and forces PHOLD low which is applied through a Tri state buffer at the CPU card to pin 25 of the Z 80 MPU Fig 2 soon as the current machine cycle is ended the MPU grants the request and acknowledges the grant by bringing BUSAK low On the CPU card this signal is inverted to become the S 100 signal PHLDA DMAG or DMA grant If the front panel has re quested the DMA the address bus is controlled by 74193 counters through Tri state buf fers ICs 15 to 17 At the same time control of the data out bus is made possible should a front panel write operation en sue Finally the CPU card Tri state buffers are disabled by the active low signals CC DSBL DO DSBL SDSBL and ADDRDSB ICs 19 to 21 are depicted as 74LS368 Tri state buffers but could be 8T98 or 8098 types as direct replacements However the 8T98 will draw more current and the 8098 will represent a larger load to the bus Alter natively 7404 7405 or 7406 types could be used with a dif ferent pin out and higher bus loading The 74LS04 cannot be used because it will sink only eight mA in output low state A bit that is at logic one will cause the indicator LEDs to be forward biased and the 10 or 12 mA should give adequate light output To load the address set the 16 sense switches SSO to SS15 to the desired location and toggle the LOAD ADDRESS switch S7 This brings the load pin on the four counters 11 to 14 low
24. Soft ware Gourmet Guide and Cook book Terry A Jackson Lombard IL More Articles on the 1802 This is a brief letter of concern directed to your magazine So far most of the articles published deal directly with the 6800 series computers or the 8000 series com puters I agree these are popular however you seem to overlook the RCA CDP 1802 MPU Certainly a large audience ex ists for this computer outcrop ping from the COSMAC Elf series Netronics Elf COS MAC Micro tutor UC 1800 and the COSMAC VIP An outlay of only 100 is needed for a basic computer Please publish more articles for the CDP 1802 COSMAC series Mike Otis Aberdeen SD I ve said it before Mike but you ve given me the opportunity to say it again and I thank you I don t have a magic hat to 20 reach into and pull out articles on a particular computer We pub lish articles that have been writ ten If you or any other 1802 owner would like to see more material on the 1802 then go directly to your typewriter do not pass but perhaps you will collect that 200 You re right about the 1802 gaining in popularity and I ll be happy to see more written about it John Computer Portraits Franchise read with interest your letter and reply in the letters column of December 1977 on the subject of computer portraits We are pres ently setting up a franchise orga nization that will allow just about
25. V9 H ocec y aSd 1 38 112 404 11 39 15 Zr d M2 x1 111 3 2 IAN HSA d 0S Y2 039 M31NI Hd 01 100 H319VHYHOD ONV 3Sv 9 1 010 19 010 2 012 Leg Ort Ott stl 828 828 820 820 828 828 828 828 828 848 828 828 BLO 929 9l 928 828 828 828 828 828 828 eoa eze 19 224 110 9 m c9 v 04 S8 8 snns 69 1 02 961 20291 202 9 1 102 91 002 991 111 941 911 9 1 1194 47179 1 11 9 1 211 9 1 111 9 1 01179 19159041 991 594 91941 91 9 1 19 594 29159941 59 90 091 9 1 151 9 1 94 94 661 9 1 tSt 9 1 179 261 9 1 Ost 9 1l 181 9 1 eel 9 1 L 9 1 L L 9 l 091 5981 191 5941 ICL e 1 5941 Let 79 21 9 1 EZL 5941 221 9 1 L2L 9 1 98815941 61179 1 211 9 l 101 9 1 01 5941 20 94 20 ICL 119 9 41 910 9 10 9 1 47079 218 9 1 L40 9 1l 21091 49
26. and dry Hunt also orders equipment from dealers and pays by check He then stops payment on the checks When contacted by a dealer about why he stopped pay ment he may say that the product was defective and is being re turned and request that another unit be shipped When Hunt was arrested in Santa Maria he had a loaded shotgun in his closet at home and he may be considered dangerous If anyone has information that may relate to this suspect please contact Detective Ernest L Kapphahn Santa Maria Police Department 805 922 7811 or Investigator Zeke Hernandez Chino State Prison 714 597 1821 55 50 Bus Manufacturers Meet All manufacturers of 55 50 bus compatible hardware met at the second Computer Faire in San Jose to discuss possible new bus signal assignments Represented at the meeting were Southwest Technical Products Corp Mid west Scientific Instruments Smoke Signal Broadcasting Gimix and The Micro Works It was agreed the uniformity of use was essential to protect cur rent and future users of the bus from the incompatibility and general chaos now being faced by S 100 bus users and manufactur ers It was agreed by everyone present that any revised or addi tional bus line assignments would be cleared with all concerned before being designed into equip ment A suggestion to change the present Phase 1 line to Slow Memory was made by Mr Chil dress of Midwest Scientific In strument
27. and one pulse each two seconds is 30 IF C A1 10 THEN UP EXERCISE RATE IN ORDER TO BRING PULSE RATE UP TO 1 TS MIN GOSUB314 NOW CONTINUE EXERCISING FOR THE NEXT TWO MINUTES GOSUB314 M 120 GOSUB264 beats per minute Collect the value of T each time after the routine has counted 15 beats Repeat each input rate about ten times and use the best eight determinations throwing out the highest and lowest T value determination per rate 3 Now enter the calibrating program listed with this article It will ask you how many data points you have and then will ask you to input the values you have collected The program then performs a line fit routine matching the points to the general formula generates a formula for aline on which the points fall It then converts this formula into the format required in line 308 of the exerciser pro gram Watch R2 it is a good ness of fit value and if it s not between 94 and 1 0 something is amiss 4 Enter the output as line 308 in the exerciser program and you re calibrated Each time you enter a T value a B1 or heartbeat rate value will be calculated using that formula An alternative is to collect enough data points to build a lookup table into the pro gram or the counter loop to produce a linear cor relation The program occupies about 4 5K of RAM and is written in D G Maxi BASIC Version 1
28. as low as 3 microseconds per pixel Versatility Accepts either interlaced NTSC or non interlaced Industrial video input Compactness Utilizes 1 170 5101 in your SWTPC 6800 or equivalent Economy The Digisector is a professional tool priced for the hobbyist The Digisector 05 68 like all Micro Works products comes fully assembled tested and burned in Only the highest quality components are used and the boards are double sided with plated through holes solder mask and silkscreen All software is fully source listed and commented The Micro Works is proud to add the DS 68 to its line of quality computer acces sores forthe hobbyist Price 169 95 The Micro Works 6800 series of computer accessories also includes PSB 08 PROM System Board regulated 12 volts B 08 2708 EPROM Programmer regulated 12 volts 119 95 124 95 99 95 104 95 236 238 240 242 244 246 248 250 252 254 256 258 260 262 264 266 268 270 272 274 276 278 280 282 284 286 288 290 292 294 296 298 300 302 304 306 308 310 312 314 316 318 320 U2708 EPROM Software UIO Universal O Board X 50 Extender Board X 30 Extender Board TIME FOR ANOTHER PULSE RATE CHECK GOSUB282 IF B1 gt 1 20 THEN242ELSE246 T BETTER SLOW IT DOWN YOUR PULSE RATE IS HIGH GOSUB314 IF B1 C 1 10 248 ELSE250 PICK UP YOUR EXERCISE RATE FORX 1TOI1E3 NEXT LETS CONTINUE TWO MINUTES REM
29. be to have the typewriter echo what is being written on the TVT screen thus requiring minimum modification of existing programs The sys Photo 5 On the left is the 56 V power supply to operate the solenoids The other large transformer is to adapt the 208 V motor to the 117 V power The circuit board with the transistors diodes and the ICs that control the solenoids are mounted on the bottom of the cradle beneath the power relay The 5 V power supply is at the rear Photo 6 The shift clutch cam and solenoid had to be added to my machine The shift cam pushes out the arm with the pulley on the upper end which pulls the rotate tape to turn the type element 180 degrees tem block diagram Fig 2 shows how this was done Two NAND gates 7400 were connected in cascade with the ECHO switch tied to one of the inputs of the second gate The two inputs of the first gate connect to the serial data line from the computer to the TVT When the ECHO switch is on the Output of the second gate echos the serial data going to the TVT When that switch is off the output is high or mark The output is con nected to the serial input terminal of an MC6850 asyn chronous communications interface adapter ACIA With the echo switch on when a character has been sent to the TVT and the ACIA has received it the ACIA interrupts the com puter through the nonmask able interrupt line NMI The computer takes the character from
30. developer is a serious skin and eye irritant Methylene chloride is an ex tremely volatile liquid This means that a room containing an open tray of the developer solu tion would rapidly have its air contaminated with substantial amounts of the vapor In a small bathroom with the windows and doors closed to make a temporary darkroom the vapor concentra tion could far exceed the recom mended peak exposure level The present federal peak limit is 2000 ppm but the National Institute for Occupational Safety and Health has recommended that it be substantially reduced Methylene chloride which enters the body by inhalation is rapidly metabolized One of its breakdown products is carbon monoxide This reacts with the hemoglobin in blood and reduces its oxygen carrying capacity The heart and circulatory system must then work extra hard to pump blood faster in an attempt to make up for the decreased oxygen supply Methylene chloride also affects the central nervous system as an anesthetic recommend that anyone us ing a developer containing methylene chloride follow the general recommendations for paint removers in Consumer Reports August 1976 page 434 e If at all possible work out 18 doors And try to stay upwind If you must work indoors make sure there s plenty of ven tilation not just from an open window or two but from a strong window exhaust fan e Wear neoprene rubber gloves and goggle
31. double sided 600K bytes each Send for their new catalog and include 25 OK Box 32040 San Antonio TX 78284 TSC started off in the 6800 software business but they re now offering some of the same pack ages their text processing in particular in 8080 code They would dearly love to send you a copy of their new 78 catalog Technical Systems Con sultants Box 2574 W Lafayette IN 47906 If that dapper gentleman looks like Dick Milewski of The Soft ware Works there s a good rea son for the resemblance If you re looking for a North Star based inventory control pro gram they have one A review of the package is coming up in Kilobaud Drop them a line for more info PO Box 4386 Moun tain View CA 94040 N 59 47 F gt Hey the folks at the Com puter Room have a couple of beautiful business systems The one Lawrence Grijalva is demonstrating in the photo is available with a cost estimat ing package for heavy duty construction and inventory control They also have a Ran dall Data Systems machine with a BMI Building Materials Industries package every thing you need for running a lumber yard 124 H Blossom Hill Rd San Jose CA 95123 Well that should do it for this time We ll finish up our little tour of the Faire next month with Part 2 more of the people and products John 41 Tiny BASIC Shortcuts Tom Pittman s Tiny BASIC
32. for N is decremented in line 310 until the data sets input in line 170 are used up The counter that starts in line 120 numbers the printed output each time a pass through the program is com pleted tried to use N to do both but could not without using more program lines Otherwise this is simply a fundamental pro gram with input between lines 100 and 170 calculations be tween lines 190 and 220 and out put between lines 240 and 290 Summary It is easy to save bytes of memory if you remember to use implied statements and state ment abbreviations The user s manual for Tiny BASIC shows what is and is not allowed Both the decimal number and number range limitation can be handled by using software math techniques multipliers PAYMENTS ARE 147 LOAN NUMBER 2 INTEREST IS 2400 MONEY OWED IS 6400 PAYMENTS ARE 133 LOAN NUMBER 3 INTEREST IS 5200 MONEY OWED IS 9200 PAYMENTS ARE 153 DONE Fig 5 Loan value two rerun to show the effect of compound in terest on the total loan value Compare the results with the sim ple interest calculation etc Line input characters until you reset your system If limited to 70 72 with prompting question mark and space can also be handled by pro gramming techniques Remember if you input more than a total of 72 characters in a single line the program will you have to reset and want to save the program already in memory then reenter the inter
33. lines for this program used principal in hundreds and rate in percent to avoid decimal percentage entry and to pre vent dividing percent by 100 to get back to a decimal percent age The math comes out right when it s printed out in line 250 then multiplied the total loan value by 100 in line 200 to make the right amount print in lines 270 and 290 Principal input in hundreds also helps avoid the number limitation problem Keeping the numbers to be operated on small limits precision but keeps the multiplication re sults in range Adding a state ment in a print line to multiply or divide etc by some factor will put the answer back in the right magnitude This is sort of like using engineering notation with a slide rule The difference is the lack of decimal numbers An input line limitation of 72 characters restricts the amount of data you can input Two character spaces are used 100 PR LOANS HOW MANY 110 INPUT N 115 PR 120 A 0 PR INPUT PRINCIPAL IN HUNDREDS INPUT P R T X P T R O 100 P 1 1 RATE IN PERCENT TIME IN YEARS 1 PAYMENTS IN MONTHS PR LOAN NUMBER A PR INTEREST IS 87 PR OWED IS O PR 5 ARE M PR N N 1 IF N gt 0 GOTO 170 PR PR DONE PR Fig 2 Second program version using implied statements and abbreviations to save by
34. me to design and construct a front panel that provides the logic to use the commercial CPU boards in an otherwise home brew system In my case the S D Sales Z 80 CPU card was available locally and was the starting point for the design Lacking software experience with the Z 80 needed a software independent unit In deed one of my major goals was to have a system with which could develop software The result was a manual front panel permitting direct access to memory for both read and write operations Armed with the 2 80 technical manual and the schematic of the S D Sales CPU card began the design The outgrowth of the effort is depicted in this article Design Considerations There were several things 26 and the very best to you Norm John especially wanted from my system First compatibility with the many commercial S 100 peripherals available Since was using the commer cial CPU card this aim was easily met only had to avoid compromising what was already there Second an expandable system up to 64K of memory and I O ports galore Basically this meant the use of Tri state buffers in an expand able bus configuration Also wanted to use wherever possible standard TTL chips that had pulled off old boards at an average cost of three or four cents wanted to avoid at all costs the use of special devices However in the interest of reducing bus loading and parts counts
35. module outside the computer mainframe and the connecting cable The individual continuous loop tape wafer less than a fourth the bulk of the standard audio cassette and holding up to 40K bytes is inserted in the slot in the front of the drive module and will save or load 4K bytes in about 5 seconds All operations are software controlled the utili ty programs are contained in an EPROM on the control board The subsystem is delivered ready to operate and is backed by a one year full warranty and a 30 day money back guarantee Exatron Corp 1030 East Duane Suite I Sunnyvale CA 94086 The Electric Pencil 11 Michael Shrayer Software 3901 Los Feliz Blvd Los Angeles CA 90027 announces the Electric Pencil Some of the new fea tures include CP M compatibil ity simple file management dynamic print formatting multi column printing cassette backup capability centering underlining and boldface The Electric Pencil II is now available on CP M standard printer versions 225 Diablo printer versions 275 System hardware must include 8080 or Z 80 based microcomputer printer video display CP M supported disk system or North Star minifloppy disk or cassette interface Tarbell or SOL The Electric Pencil I is still available for users Contact Michael Shrayer for more information Central Data Boards Central Data PO Box 2484 16 Sta A Champaign IL 61820 of fers
36. one for each key have teeth that push against six selector bails The selector bails in turn push latches from under a latch bail that is being pushed down by cams on the cycle shaft If the latches are left hooked the latch bail will operate a mechanical differential mechanism that moves pulleys to pull on the steel tapes These tapes are wrapped around two drums which rotate and tilt the type element If the six latches hooked they produce rota tion of one unit R1 two units R2 and two units R2A to the right and tilt of one T1 and two T2 units The five unit rotation R5 is an exception Latching vents five units of rotation to the left Combinations of these latches can then print any of the 44 characters on half of the type element four rows with 11 characters per row The shift operation turns the ball 180 degrees so that the characters on the other half of the ball can be printed Though all this may sound like a Rube Goldberg machine it is really a care fully designed device with interlocks to prevent im proper operation if the oper ator presses two keys ct once or if there are other timing problems Long trouble free service is obtained through wear adjusting compensation You have to take your hat off to the Selectric designers SHIFT 5 TES TI LF R2 B8S You don t have to under stand all this to get the point to control the Selectric by the
37. opened with the comment that even though was the editor of a computer hobbyist magazine I had no intention of directing myself to computer hobbyists Those in attendance included newcomers interested in home computers students profes sional people some in data pro John Craig cessing and small businessmen 1 was rather amazed at the number of times made reference to ar ticles in Kilobaud that would be of interest to those people These two groups were made up of end users or the mass market we ve been talking about If you stop and think about some of the practical ap plications programs we ve run hardware and software reviews and small business software 1 think you ll see what mean Many see this new mass market as being made up of people who simply want to take their new computer system home plug it in load a cassette program and run I agree with that concept to a point That point is where these people begin to tire of all the programs they can buy and get the itch to generate some of their own That s not hard to imagine because many of the younger generation will be programming the home computer to solve homework problems and there by exposing mom and dad to pro gramming There will be another segment of these end users most likely those with an electronics background who will start tinkering with the system by add ing new peripherals modifica tions and ca
38. output port to display registers data etc End confusing strings of discrete LEDs 6 80 7 50 7 seg 1 3 in display 7 seg display NORTH STAR SOFTWARE inventory hex and dec Variety package 1 translators memory fill electronic Design memory test games and more complete package on one double sided diskette 20 Additional double sided diskettes 5 Md Add 51 shipping and handling for orders under 20 MC or VISA welcome 24 hours 4 MIDWEST DIGITAL 863 Wood Ave Wichita KS 67212 316 722 1711 M42 Introducing Bit Pad The new low cost digitizer for small computer systems Bit Pad is the newest product from Summagraphics the leading producer of professional digitizers t has a small 11 incn active area a small 555 price tag But the list of applications is as Dig as your imagination Better than a joystick or keyboard for entering graphic information t converts any point on a page any vector any distance into Its digital equivalents It s also a menu for data entry You assign a value or an instruction to any location on the pad At the touch of a stylus 115 entered into your system Who can use it Anyone from the educator and the engineer to the hobbyist and the computer games enthusiast data structure is byte oriented for easy compatibility with small computers So you can add a power supply stand alone display cross hair cursor and many ot
39. smelling salts or respiration assistance capability Enter each heart beat as you feel it with one hand by momentarily pushing the button with the other hand To feel your pulse lightly press an index finger against one of your temporal arteries located in the temple area of your head Never press both arteries simul taneously IF B1 gt 1 20 THEN A MINUTE BREAKBEFORE CONTINUING IF B1 gt 1 20 156 ELSE164 KEEP MOVING AROUND DURING THE NEXT MINUTE TO IMPROVE BLOOD CIRCULATION M 60 GOSUB264 GOTO168 WITH A PULSE RATE B1 YOU CAN NOW REPEAT THE PUSH AWAY AND SITBACK EXERCISES 15 TIMES EACH TAKE ABOUT 2 MIN GOSUB314 ZA TAB 10 START M 120 GOSUB264 NOW LETS CHECK THAT PULSE RATE GOSUB282 IfB1 lt A1 20 THEN 192 YOUR PULSE RATE IS A LITTLE HIGH TAKE A 30 SECOND BREAK BEFORE CONTINUING GOSUB314 M 30 GOSUB264 SELECT ANY EXERCISE SUCH AS RUNNING IN PLACE THE OBJECTIVE IS GET YOUR PULSE RATE UP 3 A1 BEATS MINUTE AND KEEP IT THERE FOR ABOUT FIVE MINUTES GOSUB318 YOUR EXERCISING AND CHECK YOUR PULSE RATE IN ONE MINUTE GOSUB318 START M 60 GOSUB264 PULSE RATE CHECK AGAIN GOSUB282 IF B1 lt A1 20 THEN224 T 1 5 BEATS MIN YOU SHOULD SLOW DOWN CUT YOUR EXERCISE RATE TO ABOUT HALF OF WHAT IT HAS BEEN FOR THE LAST
40. the ACIA receive buffer converts it to the proper control byte for the typewriter and puts the byte out to the PIA After the proper time delay for type writer operation the com puter is returned to the main program The software that does all of this and controls the Selectric typewriter will be described in part two of this article 9 25 Norman Thagard M D 669 Edmonds Dr James Island SC 29412 Home Brew Z 80 System Part 1 If you want to build your own system from scratch just follow these instructions Due to the informal nature of Kilobaud we don t normally provide an author s profile with each article or even discuss author s background With Norm Thagard going to make an exception Norm was one of 8079 applicants for America s next generation of astronauts the NASA Mission Specialists who will be going into orbit aboard the Space Shuttle When the com petition got narrowed down to 208 aspirants Norm called me on the phone and told me he wanted to use the fact that he had built home brew computer system and published an article on it as ad ditional leverage with NASA Maybe it helped because he was one of the 35 selected for the mission specialist slots Congratula tions he availability of several low cost S 100 compatible Z 80 CPU boards the high cost for a medical student of com mercial S 100 systems and a burning desire to have a per sonal Z 80 system prompted
41. this hardware is to give us the ability to produce programs for sale and be sure they all work on the systems we say they will What s Coming Initially we ll be putting out programs on cassettes After that we ll probably be using more and more disks then perhaps ROMs but what will be next With the prices on video re cording systems coming down we may soon see video recorders used for program and data storage These recorders are all set up to be easily controlled by a computer Picture if you will a study course of the future on video tape It will have full television action and sound in color program your computer as it goes along It will show material and then stop and ask a question about what has been Reader Responsibility One of your responsibilities as a reader of Kilobaud is to aid and abet the increasing of circulation and advertising both of which will bring you the same benefit a larger and even better magazine You can help by encouraging your friends to sub scribe to Kilobaud Remember that subscriptions are guaran teed money back if not delighted so no one can lose You can also help by tearing out one of the cards just inside the back cover and circling the replies you d like to see catalogs spec sheets etc Advertisers put a lot of trust in these reader re quests for information To make it even more worth your while to send in the card a drawing will be held each
42. trick of the trade is valid in my view Diodes often solve a problem simpler than any other approach Diode AND S are still another method where input switching matrices for memory use can be implemented such as in Don Lancaster s TTL Cookbook Fig 6 27 p 256 Ralph W Burhans Athens OH Due Credit Just received Kilobaud No 16 yesterday the article was in there What a good feeling until I spotted the title block Oh my new 4K EPROM board from SWTP Credit needs to be given where credit is due new 4K EPROM board from APTEC The goof was not in the proof copy I received because no title block was included Harley D Johnson Oregon City OR 8080 Simulator Notes I want to commend your maga zine and Lee Stork for a func tional and useful program article the 8080 Simulator Kilobaud September 1977 p 64 After de bugging was able to adapt this program to an Intellec 8 Mod 80 to which I have access For the benefit of readers who have tried or are going to try this program here are a few notes 1 At address 134 the mne monic LSI should be LXI 2 At address 172 MVI 5 was necessary to send a line feed to my console output device a CRT terminal 3 Likewise address 138 need edMVI 2 0 give me the prop er display format 4 At address IFD my ICOM FDOS assembler creates
43. 0 It is running ona Digital Group 2 80 system with a 2 5 MHz clock and 18K of RAM This is a unique applica tion of a microcomputer in the home Automatically in putting the heartbeat data using sensors such as strain gauges or force transducers is the next step That s a hard ware problem of no small magnitude at the home brew level and would make an interesting project and article strongly recommend you read and or check with a physician before beginning any exercise program Gwe your 6800 computer the gift of sight The Micro Works Digisector opens up a whole new world for your computer Your micro can now be part of the action taking pictures like this one to amuse your friends watching your home while you re away helping your household robot avoid bumping into walls providing fast to slow scan conversion for you hams the applications abound The Micro Works Digisector 15 completely unique device its resolution and speed are un matched in industry and the price is unbeatable anywhere The Digisector and a cheap TV camera are all you need to see eye to eye with your 6800 Since operation is straightforward you don t have to be a software wizard to utilize the Digisector s extensive capabilities The Micro Works Digisector board provides the following exclusive features High Resolution a 256 x 256 picture element scan Precision 64 levels of grey scale Speed Conversion times
44. 0 1 uF ceramic capacitor per four gate pack ages or per two MSI packages When using a wiring pencil it is a good idea to check continuity of each interconnection with an ohmmeter You may generally follow the layout shown in the accom panying photograph or change it to suit your own inclinations 27 A word of advice the DEPOSIT EXAMINE NEXT and STEPPER switches will be frequently used and should be convenient ly placed The sense switches can be grouped in fours as shown for hex notation or in threes for octal Although be phenomenal space requirements may tempt you to place the sense switches as close together as possible without grouping them don t do it With such arrangement your error rate will Checkout Prior to applying power use your ohmmeter to ensure that no Vcc to ground short exists The supply connections to the 5 SINGLE STEP PRDOY 232 0 1 3 SINGLE STEP 3 44 c to cet 5 IOK esv 524 STEPPER SWITCH io 2 6 D smi gt 2 gt 2o ce C v 1 330 5 FRONT PANEL 5355 DMA bk 1 RUN PNOO ToK Ct 9 D PHLDA TE gt 2 Di T DEPOSIT 254 iQ ae D T I v f EXAMINE NExT S Las A gt 5 4896 i 2K 3 2 2 2 9 28 ICs in this project are all at the corners as is standard with TTL so make sure they are con nected to the appropr
45. 00 PAYMENTS ARE 158 DONE Fig 3 Sample run Simple interest calculations of two different loan values at three rates 43 From Fig 3 From Fig 5 Simple Int Compound Int LOANS HOW MANY interest Years Amount Equiv Int Years Amount 23 1 10 3 5200 00 11 3 5320 00 INPUT PRINCIPAL IN HUNDREDS P 2 12 4 5920 00 15 4 6400 00 RATE IN PERCENT R 3 18 5 7600 00 26 5 9200 00 TIME IN YEARS T PAYMENTS IN MONTHS X Mult Actual Loan Value Difference 240 11 3 36 40 15 4 48 40 26 5 60 1 1 331 5324 00 4 00 2 1 574 6296 00 104 00 LOAN NUMBER 1 3 2 288 9152 00 48 00 INTEREST IS 1320 Fig 4 For a loan of 4000 MONEY OWED IS 5320 line 170 runs out of data and line 320 is still greater than zero This program only calculates simple interest loans Com pound interest calculations re quire decimal numbers and raising numbers to some power The multiplier for com pounding over n periods is 1 1 where is the interest expressed as a decimal and n is the number of years or periods You can use this multiplier to calculate the approximate equivalent while percentage over the term of the loan Your calculated answer will result in a much more realistic loan evaluation made some of these calculations and Fig 4 has some examples In the program itself there are no unusual or unique pro gramming techniques There are two counting loops one starting at line 110 and the value is input
46. 15 packing refurbished e Guaranteed e Shipment no waiting e Add 45 50 for scrolling mod or do it yourself NOW Power your KIM I or other small processor from these terminals Up to 2 Amps at 5 14 25 volts Mode 3360 speeds from 300 4800 Baud numeric keypad cursor controls Edit Block Transmit search modes ASCII Keyboard with codeabie options Green phosphor 24 82 Ch lines addressable cursor RS 232 serial interface other speeds available Manual 10 Cable kit 995 Datashare IBM com patible version 1 100 e Model 3000 675 M 33 KSR Teletypes 595 ASR 33 735 Call us for service on CRTs micros main frames Leasing quantity discounts available TELECOMMUNICATIONS SERVICES CO Box 4117 Alexandria Va 22303 703 683 4019 TLX 89 623 T26 stop Nothing more will happen big to be useful l RAINBOW COMPUTING INC Supplier of Apple Wave Mate The Digital Group Southwest Technical Products Digital Equipment Corporation Computer Products Peripherals and Supplies from PerSci Computer Devices Contronix Lear Siegler Diablo Multi T ech Maxell Texas instruments Scotch Brand Magnetic Media Specialists in Design Implementation and Support of Custom Hardware Software for Business Educational and Personal Use Consulting Contract Programming Operating Systems Applications Software Experts in most major computer software including CDC BASIC COBOL FORTRAN PL1 Lisp Simula Snobol
47. 2 get L122 9 1 922 9 1 22 9 1 22 9 1 22 9 1 222 9 1l 22 9 1l 022 961 1X1 2 9 1 9t 2 9 1 t 2 9 1 29901 22994 24219941 29941 81 25941 102 9 1 902961 402961 138 INVIBYVD 0333 3N SINIUd S8 1138 8 SIS3HIN3UVd LHOIY 501314 082 082 082 082 082 082 082 082 082 082 092 00 082 082 001 082 0 91 092 082 092 082 082 082 082 02 t 41 312 2 100179 IV 9 25 5913 35 3 83441 501314 515 1 38 4 1331 801314 14 0 3 SNIVIS 591 3 5911 M319VNYHD 18184 dV 3801538 LIVA LON 31 2 0 38 LYYSN SI 501915 139 JY JAVYS 3MNVS 18184 515 3 1838 4 189218 L All 854 1415 42411 854 9 2 d 4 50 138 100 404 one 2988 NI HSfid 118 118 X 118 118 181 x x x 35 9 1 15 1n0H2 SNIVIS 9NI32349 X 8314V 318154 01 YILIVYVHD 0 35 022 059 138 11 3 IAN 198 S1S3HIN3NVd 1 918 GNIS X JV 3801539 3MVS INIUd SISJHINJYYd 1331 JY 3 YS 854 022 01 lt 854 13 404 1312 IAN 514 131 3515 3 1838 4 1331 0035 X 312 2 ININd ONV dY 38016539 4 01 11 0 35 ONV AMOW3W XY 3 OS ON 11 3 0S 534 2340438 SY 3NVS 11 SI 3583 01 IN 0d 380 32N0 NIVY9Y 1331 13185 ONY AMNYO I183ANI 35 2 27153 1 5 7212 2 0314I HS 3AVS 323 383 3SVYO 5 1n0oH2 MS d 10082 3S YQ 40S v2 3S
48. 28208 Irvine California 92714 301 948 2400 704 377 0300 714 957 0300 The SuperDEC and other Intertec products are represented in these cities Albany NY Alberquerque NM Atlanta GA Baltimore MD Boston MA Buffalo NY Charlotte NC chicago IL Cincinnati OH Cleveland OH Columbia SC Columbus OH Dallas TX Dayton OH Denver CO Detroit MI Hartford CT Huntsville AL Houston TX Indianapolis IN Jacksonville FL Kansas City KS Los Angeles CA Louisville KY Madison WI Memphis TN Miami FL Milwaukee WI Minneapolis MN Nashville TN New Haven CT New Orleans New York NY Oklahoma City OK Omaha NB Philadelphia PA Phoenix AZ Pittsburgh PA Portland OR Providence RI Raleigh NC Richmond Rochester NY Sacramento CA Salt Lake City UT San Antonio TX San Diego CA San Francisco CA Seattle WA St Louis MO Syracuse NY Tampa FL Tulsa OK Virginia Beach VA Washington DC International offices located in Australia Austria Canada Denmark England France Germany Holland Switzerland Taiwan 10 Photo 2 Bob Lentz president and master thinker An 015 Fig 1 Shannon Sherrick daughter of the Malibu 160 s designer Mike Sherrick Photo 3 Jill Lentz marketing and Ann Curtis 1 secretary Computer Portraits from Micro Works Computer portraits have fas cinated me for several years but not for the reason you might think The electronics the soft ware and the hardware of the syst
49. 55 U3 SN7404N Resistors R 1 18k 74 W 50k 10 Turn 47k W 1k 14 W Capacitors C 1 01 uF Disk Ceramic C2 01 uF Polystyrene High Stability Power Supply not shown H8 system Baudot printers use five information bits rather than the seven bits used by ASCII printers to print 52 char acters Even though ASCII tele printers can print many more characters than Baudot ma chines there are only a few pro gramming characters lacking in the five level printer By assigning arbitrary sym UART 12 Required on Pin 2 12 Not Required UART Timer Hex inverter Potentiometer A power supply capable of providing 5 12 and Loop current if required is necessary to operate the interface circuitry A suitable supply having in addition to the above a 12 volt regulator loop keying transistor trans former and solid state motor control relay is available in fit form from Eclipse Communications 5 Westwood Drive San Rafael CA 94901 The RP 400 Power Supply Kit can be obtained for 71 25 plus tax in California plus 2 postage and handling Table 1 Interface parts list 46 bols to cover the desirable ASCII characters not available in the Baudot set the missing characters can be accom modated The following assign ments have been made in this driver Back Space X Percent C Asterisk X Plus P Less Than lt 40 Equal E Greater Than gt G At
50. 6800 Owners Look Out I recently purchased Practical Microcomputer Programming The M6800 by W J Weller Northern Technology Books 1977 21 95 am very disap pointed with the book and hope you will not promote it Here are 19 complaints 1 There no equipment block diagrams such as to de scribe programming models of the MPU PIA or ACIA This isa particular disadvantage when try ing to describe the behavior of the peripheral chips 2 There is no description of the hardware interrupt signals even though there is a chapter on inter rupts Also this chapter contains inaccurate or misleading state ments 3 The book departs from Motorola assembly language with several pseudo ops with some of the number base conven tions and with indexed address notation 4 The book uses no flowcharts to outline or generalize programs 5 The chapter on floating point arithmetic could have been written for any computer or microprocessor It had no real how to do it information and did not even mention any actual floating formats I feel that the book is not well organized but this I know is a subjective matter Who am I MSEE with ten years experience on minis and in terfacing Owner of Altair 680 and MEK6800D2 kit Instructor moonlight job on 6800 system at Midwest College of Engineer ing 31 years as W9CUP I do like Barden s book re viewed in January 1978 Kilo baud and the Scelbi 6800
51. 9 ve d 5014 X 0194 ISN YO 9 22 18432434 02 0442 351 80 CH OLZE 350 94 i 32 4 18v1S 0112 06 2 Ose 0 524 06 0801 0821 0 91 0 0811 0 lt 0021 O82 086 Orel oael 00 099 0991 091 0 1 Ots 09 0221 0061 0 9 0 0 001 0491 0 0612 09 016 0502 0116 0211 021 02 02 lt 09 0921 0201 026 09 0911 0981 024 0991 0291 091 029 01 059 0211 091 096 024 0 12 09 0221 0921 099 082 092 082 082 082 092 082 082 112 sez She 62 OL 21 91 Ll 211 921 t Z 50 898 291 Ott 470 52 eco 221 90 22 0910 tol 612 9 LSE 602 1183 eL 219 2 240 90 921 201 988 911 991 291 910 290 lt lt 59 e 918 9 50 24 12 9 0 90 998 828 828 828 828 828 022 ae 2 9 28 11 ZLE ICL LLC ICL 2 9c1 10 lt 9 98 9 1 802994 1 0 9 1 0 lt 9 20 961 90294 90 LL2 9 1 912 9 1 12 9 1 12 9 1l L 2 9FL 2127 9 1 LL2 9 1 01279 1 192 9 1 992 9 1 92 9 1 92 9 1 92 9 1 292 961 L92 9SL 092 9 1 2 9 1 9 2 9 1 2 9 1 62 981 2 9 1 24249941 52 94 042994 L 2 9 1 9 2 9 1 2 961 2 9 1 2 9 1 2 279 1 249 1 Q 2 9 1l 1 27 9 9 2 9 1 422994 e 2 9 1l 2 9 2 2 9 1 Le 2 9 1 ec
52. AIN IN THIS SESSION M 120 GOSUB264 THIS SEQUENCE SHOULD BE REPEATED THREE TIMES PER WEEK SEE YOU IN TWO OR THREE DAYS END E O 1 50 E E 5 FORX 1T02800 NEXT T TAB 10 E SECONDS FORX 1TOO9 NEXT IFE M THEN EXIT280 NEXT W RETURN i PRESS THE BUTTON AFTER EACH BEAT KEEP MOVING PROCEED WHEN YOU ARE READY T O B O X INP 1 IFX 255 THEN290 Y INP 1 T T 1 IF Y lt gt 255 THEN 1 IF Y lt gt 255 THEN ZB IF B 15 THEN306 GOTO294 YOU B1 INT EXP LOG 85440 83 T 1 2237 RATE B1 BEATS MINUTE RETURN FOR X 1TO 4E3 NEXT RETURN FORX 1T016 Z NEXT RETURN HERE S LOOKING AT YOU KID 29 95 Casette tape 9 95 24 95 29 95 22 95 Visa and Master Charge Accepted P O BOX 1110 DEL 82014 714 756 2687 M31 35 John Craig A Tour of the Faire Part 1 Kilobaud s editor John Craig takes a look at some of the people and products that made up the San Jose show he Second West Coast Computer Faire What a show always enjoy getting out for a good convention and this one was no exception It occurred to me that you folks who couldn t make it would also like a peek at what the show had to offer Therefore took my camera along and shot pictures like crazy sin cerely hope you find it as inter esting and entertaining as did As a matter of fact l d appreci ate any feed
53. Charleston Rd Mountain View 94043 Hey that RCA VIP Video Inter face Processor is quite a little machine The price is kind of high 275 kit but it sure is a snap to create video patterns and games l d sure like to see it made a little more affordable because the 1802 has a lot go ing for it RCA Solid State Box 3200 Somerville NJ 08876 Dr Curt Childress president of Midwest Scientific Instruments is on the left with Midwest s super 6800 system and their new double sided disk system Curt borrowed copy of Issue 10 of Kilo baud and entered the Rugg Feldman benchmarks and he and Wayne Green are checking out the results in the photo on the right At 1 6 MHz the MSI 6800 came up with the following mind blowing speeds 1 5 sec 2 5 sec 3 6 sec 4 10 sec 5 9 sec 86 12 sec 7 15 sec Furthermore the system can be run at even higher clock speeds Their Catalog 82 is chock full of 6800 boards peripherals and whatever send for it 220 W Cedar Olathe KS 66061 38 Would you buy a reconditioned Diablo 1995 or QUME based terminal 2495 from that gentleman standing in the background Sure you would because he s Ken Widelitz attorney at law author of Kilo baud s Legal Business Forum and president of COMPUTER TEXTile the company offering those terminals 10960 Wilshire Bivd Suite 1504 Los Angeles CA 90024 That s Mike Sherrick the de signer of the fantastic Malibu pr
54. IONS RELATED TO THE FIRST LEVEL EXERCISES DESCRIBED IN TOTAL FITNESS IN 30 MINUTES A WEEK BY L E MOREHOUSE THE THREE FUNCTIONS ARE SEQUENCE TIMING AND PULSE RATE DETERMINATION TO CHECK PULSE RATE FIRST LOCATE YOUR PULSE BY PRESSING AN INDEX FINGER AGAINST ONE TEMPORAL ARTERY AT THE SIDE OF YOUR FOREHEAD TEMPLE USING THE OTHER HAND SHARPLY PUSH THE BUTTON IMMEDIATELY FOLLOWING EACH HEART BEAT IF CORRECTLY ENTERED A SINGLE NUMBER WILL APPEAR ON THE SCREEN AVOID HOLDING THE BUTTON DOWN TOO LONG MULTIPLE ENTRIES CAN RESULT 15 BEATS WILL BE ENTERED AND THEN YOUR PULSE RATE WILL BE AUTOMATICALLY DISPLAYED THE EXERCISE SEQUENCE IS 1 LIMBERING UP 1 MIN 2 MUSCLE BUILDUP 4 MIN 3 CIRCULO RESPIRATOR Y CONDITIO NING 5MINS THE REFERENCED TEXT SHOULD BE READ BEFORE PROCEEDING FURTHER WHAT IS YOUR AGE 34 YOUR BEGINNING TRAINING PULSE RATE IS 111 BEATS PER MINUTE BEGIN WITH ONE MINUTE OF LIM BERING EXERCISES SUCH AS 1 STRETCHING 2 TWISTING 3 BENDING EASY DOES IT LIMBER UP SLOWLY START 5 SECONDS 10 SECONDS 60 SECONDS ONE MINUTE NEXT UP 4 MINUTES OF MUSCLE EXERCISES TO ADD MUSCLE TISSUE DO 15 PUSH AWAYS AND THEN 15 SITBACKS IN APPROXIMATELY THE NEXT TWO MINUTES THEN CHECK YOUR PULSE RATE COUNTDOWN TWO MINUTES FIVE SECONDS AT A TIME NOW LETS CHECK YOUR PULSE RATE PRESS THE BUTTON AFTER EACH BEAT KEEP MOVING PROCEED WHEN YOU ARE READY 1 2 3 5
55. IVE SECONDS TIME THIS SEQUENCE SHOULD BE REPEATED THREE TIMES PER WEEK SEE YOU IN TWO OR THREE DAYS READY Sample run Program listing continued on following pages 10 GOSUB318 12 8 EXERCISER 14 16 5 PROGRAM PROVIDES THREE 18 FUNCTIONS RELATED TO THE FIRST 20 LEVEL EXERCISES DESCRIBED IN 22 TOTAL FITNESS IN 30 MINUTES 24 WEEK BY L E MOREHOUSE 26 GOSUB314 GOSUB318 28 THE THREE FUNCTIONS ARE 32 SEQUENCE TIMING AND PULSE RATE 34 DETERMINATION 36 GOSUB314 GOSUB318 38 UNE CHECK PULSE RATE FIRST 40 X LOCATE YOUR PULSE BY PRESSING 42 AN INDEX FINGER AGAINST ONE 44 TEMPORAL ARTERY AT THE SIDE OF 46 YOUR FOREHEAD TEMPLE GOSUB314 48 USING THE OTHER HAND SHARPLY 50 PUSH THE BUTTON IMMEDIATELY 52 FOLLOWING EACH HEART BEAT 54 GOSUB314 33 34 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 234 IF CORRECTLY ENTERED SINGLE NUMBER WILL APPEAR ON THE SCREEN GOSUB314 AVOID HOLDING THE BUTTON DOWN RESULT GOSUB314 15 BEATS WILL BE ENTERED AND THEN YOUR PULSE RATE WILL BE AUTOMATICALLY DISPLAYED GOSUB314 GOSUB318 THE EXERCISE SEQUENCE IS 1 LIMBERING UP 1 MIN 2 MUSCLE BUILDUP 4 MINS 3 CIRCULO RESPIRATORY CONDITIONING 5 MINS GOSUB314 GOSUB318 THE REFERENCED TEXT SHOULD
56. If you find you don t need COMPUTER DIGEST just write cancel on the invoice we send you and owe nothing If you want to con tinue to read COMPUTER DIGEST simply pay the 40 invoice we send We have found this is the best way to introduce businessmen to this newsletter This way we take all the risk so you have nothing to lose by trying this publication North American Building 401 N Broad St Philadelphia PA 19108 send me COMPUTER DIGEST also incorporating OPTICAL Yes SCANNING NEWS I understand can look at 2 issues and if not satisfied will owe nothing can write cancel on the bill and owe nothing If like the newsletter will pay the 40 bill receive Bill company for 40 Bill me for 40 Payment enclosed Title Howard L Nurse 665 Maybell Avenue Palo Alto CA 94306 Baudot er Murray Meet the 8 TREE ee te eee eo There is an inexpensive way of obtaining reliable and quiet hard copy for your home system and an old five level code teletypewriter is the answer Publisher s note The Baudot referred to in this article is actually Murray code as per my remarks on page 4 Have we all been the victim of dastardly French revisionism plot Bi teleprinters fre quently available as sur plus for next to nothing can be used with the driver described here as a listing device for your Integrated Circuits U1 AY 5 1013A U1 Alt 3 1015 U2 5
57. ONE MINUTE GOSUB314 To help prevent multiple entries caused by holding the button down for too long each beat is displayed on the video screen as it is recorded Try it a few times it won t take long to get the hang of it If you have trouble two solutions are potentially help ful 1 Increase the timing of the counting loop by chang ing the software 2 Add some hardware in the form of a nonretriggerable one shot between the push button and the input port Counter Calibration Each time through the counting loop the variable T is incremented Calibration was not as easy as expected however because the rela tionship between pulse rate and T turned out to be non linear After collecting a few data points and cranking them through linear and ex ponential curve fit routines obtained a 99 8 percent fit using the power curve line fit routine on an HP 65 programmable calcu lator Realizing a lot of people don t have access to this resource l ve written a routine in BASIC that you can enter into your micro computer for calibration of the counting loop on your system Here s how to use it 1 Enter the exerciser pro gram or just the counting loop if you prefer 2 Collect three or more data points by entering known rates which can be generated by carefully watching the sweep second hand of a clock One pulse each second is 60 beats per minute two pulses each second is 120 beats per minute
58. OW 100 H1 LOG X Z LOG Y 2Z 110 H H H1 120 J1 LOG X Z 130 J3 J3 J1 140 J2 LOG Y Z 150 J4 J4 J2 160 K1 LOG X Z LOG X Z 170 180 L1 LOG X Z 190 L2 L2 L1 200 M1 LOG Y Z 210 1 220 Q1 LOG Y Z LOG Y Z 230 Q Q Q1 240 NEXT 250 J J3 J4 W 260 L L2 L2 W 270 B H J K L 280 A EXP M W X B L2 W 290 R2 H J H J K L Q M M W 300 B B 310 320 CORRELATION FACTOR R2 330 USE THE FOLLOWING EQUATION FOR LINE 308 IN THE EXERCISER PROGRAM 340 Z B1 INT EXP LOG A T 1 Bs 350 END 32 Calibration routine book entitled 7 ota Fitness in 30 Minutes A Week by Morehouse and Gross Simon and Schuster NY 1975 later purchased a copy read it and began following much of the advice and direction it contains Very briefly building and or maintaining physical fitness is accom plished using three minute exercise sessions per week During each of these sessions you monitor your pulse rate and attempt to maintain it near a predeter mined value Each session re quires more work to produce the same pulse rate as your condition improves Timing the segments in each ten minute session and timing six seconds to obtain a pulse count turned out to be a pain in the neck For ex ample if you begin at 06 59 22 and time one minute then you should stop at 07 00 22 and then begin timing the next two minut
59. POSIT C6 This is the op code for add accumulator immediate and will result in the addition of the byte stored in the next sequential memory location to the contents of the accumulator The result will re main in the accumulator 6 DEPOSIT 08 This number will be added to the 08 already in the accumulator 7T DEPOSIT 32 This is the op code for load memory imme diate and will cause the con tents of the accumulator to be 30 memory specified by the next two program bytes 8 DEPOSIT 10 The low order byte of a two byte ad dress is specified first in a Z 80 8080 system In a 6800 system the high order byte is specified first In our case the address in which the ac cumulator contents are to be stored is XX10 where XX is specified in the next memory entry 9 DEPOSIT 00 The high order byte of our storage ad dress is now specified to be 00 The complete address is 0010 10 DEPOSIT 76 This is the op code for a software HALT its execution will halt the MPU causing it to execute NOPs no ops until interrupted or reset The indicated address should now 08 11 LOAD ADDRESS 0000 The data LEDs should indicate 3E Using EXAMINE NEXT toggle through the first seven memory locations to verify the program you have just entered 12 Place the SINGLE STEP switch in the SINGLE STEP mode return DMA to RUN mode and activate the RESET The address indicators will show 0000 and the d
60. Picking up the other one he said Then we have this one which is filled each month with mostly light reading short ar ticles and very little that you can really sink your teeth into Two magazines one which is too technical in content and the other too light He suggested that since Kilobaud rather than Byte could more likely balance things out I should consider in cluding at least one or two heavy articles in each month s issue I m inclined to agree with what about you Heck this business of putting together a magazine is a snap All you have to do is provide material that will satisfy tens of thousands of read ers all with varying interests The Southern California Swap Meet Got anything scheduled for Ju ly Ist If so get busy and cancel it and don t plan to go out of town for the July 4th weekend that is if you live in Santa Barbara CA If you don t then by all means plan to drive there for the Southern California Swap Meet on July Ist People will be coming from as far east as Phoenix as far north as San Francisco and as far south as San Diego so there s no reason for you not to come Next month I ll include a map showing how to get to it and a photo of the beautiful building the event will be held in And that s what it s going to be an event computer hobbyists hams and electronics experimenters all getting together for a goo
61. Problem definition and program design 14 Debugging and testing 15 Documentation and redesign 16 Sample projects es awe Table 1 8080A 8085 Assembly Lan guage Programming has many more points to make too many to cover here This is not a one evening book If you have an 8080 or 8085 improved 8080 CPU or have access to one the ideal learning situation is to try the examples as you go along Each chapter has in addition a series of problems for which clues but no coded solutions are supplied These give you a chance to try your hand at assembly language programming Particularly interesting is the discussion on various program ming methods flowcharting modular structured and top down Although no one method is touted as being the best each is explained and advantages and disadvantages presented Clearly the author leans toward struc tured programming Major statements are printed in boldface type and explana tions to these statements are printed in a lighter type The tendency is to read only the bold face sentences until you come to one that you don t understand at which time you read the lightface type for clarification Out of habit I found myself reading it all This is definitely a software Oriented text but an amazing amount of hardware information is given in the I O and interrupt chapters probably enough to implement any of the designs dis cussed So far I hav
62. SPSS COMPASS MACRO 6800 amp Z80 assembly languages 10723 White Oak Ave Granada Hills Ca 91344 213 360 2171 R10 By subscribing to COMPUTER DIGEST you have the facts you need about computers and optical scanning With this information you can act immediate ly on new business opportunities Subscribe and each month you get A 12 page newsletter digesting the im portant news in the computer and optical scan ning field There is coverage of new equipment new optical scanning and computer forms who is expanding who is getting promoted a wide variety of facts all written in concise style so you can read the reports in minutes Over 50 news reports in each issue cov ering new equipment new uses of computers and scanning equipment new products and software Not only can you find new markets but the reports will help you solve customer Send to COMPUTER DIGEST Try COMPUTER DIGEST And Get A Digest of EDP amp Scanning News problems because you will be more knowledge able about computers and optical scanning It s a timely summary of what is being written about computers and optical scanning in the business press You save reading time plus you can be sure of getting hundreds of new items of interest each year To subscribe just complete the form below and mail it back The newsletter is fully guaran teed Read 2 issues see if you can use the infor mation
63. THANK YOU RATE 120 BEATS MINUTE GOOD WITH A PULSE RATE OF 120 YOU CAN NOW REPEAT THE PUSH AWAY AND SITBACK EXERCISES 15 TIMES EACH TAKE ABOUT 2 MIN COUNTDOWN TWO MINUTES FIVE SECONDS ATA TIME NOW LETS CHECK THAT PULSE RATE displayed Frequency Pulse Rate Counter begins in line 290 When called up the subroutine watches input port one for any change from 255 which The pulse rate subroutine it sees if all eight lines are left PRESS THE BUTTON AFTER EACH BEAT KEEP MOVING PROCEED WHEN YOU ARE READY 1 THANK YOU RATE 123 BEATS MINUTE SELECT ANY EXERCISE SUCH AS RUNNING IN PLACE THE OBJECTIVE IS TO GET YOUR PULSE RATE UP TO 111 BEATS MINUTE AND KEEP IT THERE FOR ABOUT FIVE MINUTES BEGIN EXERCISING AND CHECK YOUR PULSE RATE IN ONE MINUTE START COUNTDOWN ONE MINUTE FIVE SECONDS AT A TIME PULSE RATE CHECK AGAIN PRESS THE BUTTON AFTER EACH BEAT KEEP MOVING PROCEED WHEN YOU ARE READY 1 Erc 5 THANK YOU RATE 153 BEATS MINUTE AT 153 BEATS MIN YOU SHOULD SLOW DOWN CUT YOUR EXERCISE RATE TO ABOUT ONE HALF OF WHAT IT HAS BEEN FOR THE LAST ONE MINUTE NOW CONTINUE EXERCISING FOR THE NEXT TWO MINUTES COUNTDOWN TWO MINUTES FIVE SECONDS AT A TIME TIME FOR ANOTHER PULSE RATE CHECK PRESS THE BUTTON AFTER EACH BEAT KEEP MOVING PROCEED WHEN YOU ARE READY 1 rd THANK YOU RATE 130 LETS CONTINUE TWO MINUTES REMAIN IN THIS SESSION COUNTDOWN TWO MINUTES F
64. The Small Computer M kilobaud Understandable for beginners interesting for experts June 1978 Issue 18 2 00 DM 7 50 Sfr 8 10 Ffr 16 0 UK 2 Emerson Brooks Norman E Thagard M D Al Gerbens John Craig Charles R Carpenter Howard L Nurse Michael Slater Edward Copes E Dan Dederick Clint H Woeltjen Paul J Terrell Mac Oglesby William Nichparenko Jeffrey G Towle John A Lehman Ray Graham 3 Joe Roehrig Dr Jack W Crenshaw Dr Mark Boyd Dr Lance Leventhal 22 26 72 76 84 90 92 100 Taming the I O Selectric Part 1 hardware interface Home Brew 2 80 System Part 1 front panel construction A Strategy for Healthy Living computerized exercise fitness program A Tour of the Faire Part 1 some of the people and products Tiny BASIC Shortcuts overcoming some limitations Baudot er Murray Meet the H8 8080 2 80 or 8085 Intel s latest deserves a closer look One Keyboard Hex and ASCII simple converter circuit Is the Malibu Model 160 the Printer for Your Business System The Great Computer Conspiracy a humorous look into the future Personal Computer Shows some thoughts on the future Cross Country Balloon Trip you and your 58 52 Transfer Vectors vs Absolute Addressing a better approach Error Correcting Codes not as difficult as you think ASCII to Baudot er Murray the Hard Way Bowling Scores for Dollars
65. XTA 42 HOW SHALL I PLAY 1 5 2 600D 44 INPUT 3 FAIR 4 rQ 46 09 lt 1 09 1 09 gt 4 09 4 50 FORA 41TOS6 FORA1 0TOS 60 W A1L2A A1 16 403 1 70 57 076 1 1 NNEXTA1NNEXTA 72 DAT 51 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 5 9 13 2 56 10 14 74 DATA3 7 11 15 4 8 12 156 1 6 11 16 4 7 10 13 1 22 43 64 76 5 22 239 56 9 26 43 60 13 26 39 52 2 22 42 62 14 26 38 50 78 3 23 43 63 15 27 39 51 4 23 42 61 8 23 38 53 12 27 42 57 16 27 38 49 80 FORA 1TO64 S S NSCA ZONNEXTA 83 DATA 1 21 41 61 1 18 35 52 4 19 34 49 4 24 44 64 84 DAT A13 25 37 49 513 30547564516 31 46 61 16 28 40 52 85 PRINT YOUR MOVES ARE UU AND I M CC 86 1 075 1 0 2 1 1 87 3 3 1 9 2 9 88 6507087 89 9 2 3 1 90 GOSUBLOOO INPUT YOUR BOARD 100 A A1 1 16 4A2 gt 118 IF1 ATHEN118 POSITION 7 1 2 5 lt gt 11856070120 118 PRINT ILLEGAL 5507090 120 S AI 1 S Ar2A U 125 U2 A U4 1 GOSUB1400 190 MS O FORA 1T076 IFV A 4THEN410 198 IFV A 15STHENMS A 199 5 lt gt 365 200 M3 9 204 1 0 205 FORA 1T064 continued on page 110 12 222 606 90208 OD
66. a Australian Distributor Katherine Thirkell UK Distributors L P Enterprises i published monthly by 1001001 inc Peterborough NH 03458 Subscription rates in the US and Canada are 15 tor one year and 536 for three years in Europe erscheint mon tathich be FachzeitechrittenvertrieD Monika Nedela 7778 Markdort Marksit 3 Abonnement OM 70 pius Porto 7 20 gesetr MWST Str 81 plus Porto 20 Australia For subscriptions write Katherine Thirkell Sontron instruments 17 Arawatta St Carnegie 3163 Austraua UK 420 ster inglyear LP Enterprises 313 Kingston Rg ord Essex iG England Please write for other foreign rates Secondciass postage paid at Peter borough NH 03458 and a additional mailing offices Publication 346690 Phone 65033924 3873 contents copyright 1978 by 1001001 inc INCLUDE OLD ADDRESS AND ZIP CODE WITH ADORESS CHANGE NOTIFICATION This is the latest Extensys system It is approaching the top end and it isn t cheap either This is an formance microcomputers ET a lt i amp 4 cellent example of how far things have gone with micros Here s a view of the main part of the PET produc tion department The front line is brand new PETs that are being checked out with diagnostic pro grams to make sure they work shown If your answer is ri
67. a 16K RAM board specially designed for use in S 100 com puters The dynamic memory board uses a reliable refresh method that inserts cycles be tween the computer s normal ac cess cycles The 16K RAM board uses less than one half the power of a comparable static RAM board CD s board comes completely assembled tested and burned in just plug it in and start using Each board also comes with a full one year warranty Price is 289 There is capacity on the board for up to 32K RAM 475 or add 16K for 200 S 100 extender board assem bled and tested is 110 The 2650 Computer System board retails for 275 System board features include 80 x 16 line display 2650 microprocessor 300 baud cas sette interface supervisor pro gram two parallel ports one in put and one output and 2048 bytes of read write memory Naked Terminal Cuts Dumb Terminal Costs Dynabyte Inc lowers the cost of a dumb terminal with its Naked Terminal an S 100 module that functions with a key 4 4 s 1 4 S 4 Northwest s 85 P board and video monitor The Naked Terminal priced at 395 displays 80 characters by 24 lines using both uppercase and lowercase characters ina 5 x 7 font Half duplex full duplex and a block mode that allows editing before transmission are features of the Naked Terminal Editing is aided by an addressab
68. alent of binary byte is 1400 Baudot machine prints A 2 Assume is the ASCII character Binary byte for is 10000101 Octal equivalent of binary byte is 2050 Baudot machine prints E 3 Assume 5 is the ASCII character Binary byte for 5 is 01000010 Left parenthesis No parenthesis Uppercase FIGS Lowercase LTRS Baudot character Right parenthesis gram to another For example the following describes a typical use of the driver with the H8 editor and assembler 1 Load ASCII Baudot driver from cassette tape 2 Load reconfigured H8 editor 3 Push GO The Baudot printer will now print each character sent to the CRT with substitutions where required 4 Write and or edit source code 5 Save source code on cas sette tape 6 Load reconfigured H8 as sembler 7 Push GO The assembly will proceed normally with all parenthesis Octal equivalent of binary byte is 1020 Fig 3 Lookup table byte structure Load Distribution Tape Change High Memory using Reconfigured High Memory below Change Pad from 4 to 1 optional Record Heath program using SAVE Proceed to instructions on Table 4 Total User RAM Actual Dec imal Limit 12287 16383 20479 24575 28671 32767 36863 40959 Actual Oc tal Limit 057377A 077377A 117377A 137377A 157377A 177377A 217377A 237377A Begin Equ 056000 076000 116000 136000 156000 176000 216000
69. an sistors and supply 48 V to the solenoids The solenoids in the type writer operate trip type mechanisms that is when a solenoid is energized it trips a latch and then even if the solenoid is turned off the function is still enabled To prevent the typewriter s being left in some unknown char acter condition the CA2 line interlocks the CK and SH functions so that none of the type element control func tions can be tripped while the typewriter is off My Selectric had no shift mechanism when got it Since a shift is necessary to get all the desired characters had to add it to the machine bought all the necessary parts except the solenoids from the IBM Parts Center for about 20 and used an old relay to operate the shift clutch mechanism With this arrangement the shift circuit must be energized whenever shift up is required The standard IBM shift circuit uses two latching solenoids with being energized to trip the shift up condition and the other to trip the shift down condition If your Selectric has the standard shift solenoids you will want to change the cir cuit shown by providing an other transistor to operate the second shift solenoid and two one shots with about 20 milliseconds on time to drive the two shift solenoids The shift line switching on should then trigger the up shift one shot and when the shift line switches off the down shift one shot should be triggered The 5 V powe
70. and an international rep organization to get us into every country Programmers can do a lot worse than get in touch with Kilobaud about publication and distribution of their programs They must be complete and ready to go with thorough documenta tion The deal is simple 20 per cent royalty on our receipts This is about five times the going rate and we hope that we can establish this as a norm for this field by starting it out that way and main taining this percentage What kind of programs are needed Just about anything for the TRS 80 can be instantly distributed At present the pro grams should fit the 4K systems but it won t be long before we ll be needing most programs to work with the 16K systems Almost anything will go for the too 8K systems In the long run we will be able to do best for programmers who work on what we call vertical systems These would be program packages that would enable com puter stores to sell complete sys tems to specific businesses Let s say a programmer has a good friend who runs a moving van service I picked that at random by opening the Yellow Pages He would then consult with his mov ing friend and develop a program package that would do everything a moving van firm could want everything Once the package was done and carefully checked with a cou ple local van firms for accuracy and completeness we would package it and sell it through computer stores S
71. any other items You cannot believe the incredible line of computer systems components and peripherals Jade is carrying these days Their spring catalog will make you drool 5351 West 144th St Lawndale CA 90260 37 577 eu 1 42 7 56 37 Du 1 7 154 a 0 H 2 2 amp IC ch PAL ali Tandy was there in force with many new goodies for the TRS 80 Don French merchandising mgr for Tandy Computers is behind the TRS 80 on the left His head is directly above their new elec trostatic screen printer which sells for 8599 and spews out printed copy at 2200 characters per second They also had their new minifloppies and business systems line printer up and going right photo Be sure to send off for their new 1978 catalog it looks like they re carrying every brand on the block 1500 One Tandy Center Ft Worth TX 76102 I think really captured the flavor of the moment here The man on the left was a serious shopper who stopped by the Cromemco booth and hit Harry Garland president of Cromemco with some good questions about his system As you can see Harry thoroughly enjoys himself when it comes to answering such ques tions and pointing out the merits of his system If you re shopping around perhaps you should check into this Cadillac of S 100 systems Send for their new Spring Microcomputers Peripherals catalog 1 Cromemco 2400
72. ased with the computer portrait system his company has developed as the gentleman on the left who just had his picture taken PO Box 1110 Del Mar 92014 S D SALES CO ORDER BY PHONE CALL TOLL FREE 1 800 527 3460 SD COMPUTER PRODUCTS PM o mm m 97 P keep hearing more and more good things about the service and products from S D Sales and they sure were doing a brisk business at the Faire Bet they ll send you their catalog if you write for it or better yet just check their ads in Kilobaud Is it Dynabyte or dynamite Let tell you these folks some exciting things going On the left we Mike Watts president of Dynabyte standing in front of their 2 80 based dual minifloppy system and their new double sided double density Shugart floppy system They have a rather unique dedicated controller board shown in the middle photo which uses BASIC which is why it s called a BASIC Controller They were using the controller to run the two robots shown in the right photo and they sure were a hit I think it was the robots that attracted the crowds but it could have just as easily been Pam Farnsworth the young lady minding the cables and the booth They have several other interesting products you might want to check into drop a line 4020 Fabian Way Palo Alto CA 94303 1M uyt a 1L OMAHING
73. ata LEDs will display 3E Activate the STEPPER switch once The ad dress will now be 02 and data will be C6 Address 0001 will appear to have been skipped but in fact will have been ac cessed and 08 will have been loaded into the accumulator As the MPU does not enter wait states until instruction fetch cycles occur it will always ap pear to skip certain locations Continue toggling the STEP PER switch until the HALT in struction is encountered 13 Now return the DMA switch to DMA mode and then move the SINGLE STEP switch to CONTINUOUS LOAD AD DRESS 0010 and the result of the addition 10 should ap pear on the data LEDs 14 DEPOSIT 00 in location 0010 Try now to execute the same program in CON TINUOUS mode by moving the DMA switch to DMA and tog gling RESET The address indi cator will show 0008 indi cating that program execution is complete and the MPU has halted Return the DMA switch to DMA and LOAD ADDRESS 0010 The result 10 should once again appear on the data LEDs Conclusion This article has described a simple manual front panel that can be combined with commer cial S 100 Z 80 CPU boards to provide a working Z 80 com puter system This will allow the user to bootstrap tape pro grams into his machine and to develop simple routines It is an excellent way to experiment and familiarize yourself with the Z 80 instruction set It is probably the cheapest way to assembl
74. back on how you feel about the effort was little concerned with the length If you re looking for software for home or small business you ll find it here If you re look ing for the latest in mass stor age you ll find that also Ter minals You bet New low cost systems one or two Boards and components all over the place Finally some of those miscellaneous pieces of hardware you ve been hoping someone would develop for your system What the heck mention that you saw it baud when you drop a line to these companies OK Not all is well in phy land I m afraid shot seven rolls of film at the Faire You re going to be seeing the results of six rolls and l m going to be looking for a new film processor There are quite a few companies large and small who didn t make it into this write up because of that goof and l m truly sorry Come along with me and I ll give you a grand tour of the Sec ond West Coast Computer Faire and above all enjoy yourself 36 OK TRS 80 owners here it is the first computer cassette magazine CLOAD Magazine arrives by first class mail each month on a C 30 cassette for 24 a year Should be in teresting PO Box 1267 Goleta CA 93017 Casu E B RURSUS 752 Kinda show offish don t you think Although it sure did the trick when it came to attracting crowds Bob Lentz the president of Micro Works is as ple
75. c line cord and con nector cable The unit is enclosed in a Bake lite case with aluminum bottom plate and rubber feet It is 6 8 x 5 6 x 3 inches and weighs 3 5 Ibs Price is 37 New Glitch Grabber from Extensys A board interconnection de vice from Extensys Corp signif icantly reduces noise glitches and jitter on the S 100 microcomput er bus and carries a suggested retail price of 79 50 in single quantities large volume dis counts available Called the Glitch Grabber the printed circuit edge connective device maintains clean signals on the notoriously noisy S 100 bus safe guarding the low tolerance volt continued on page 111 17 Board makers Take Note Your otherwise fine article on making printed circuit boards Kilobaud April 1978 fails to give instructions and precautions for handling the chemical used to develop the photoresist coated boards The resist developer recommended is of completely different nature than the chem icals normally encountered by the home photography enthusiast I m sure that your readers aware that the resist developer is flammable and will take precau tions to exclude potential ignition sources They may not be aware that methylene chloride is the ac tive ingredient in paint remover As such it will rapidly ruin any painted or varnished surface with which it makes contact A more serious consequence of splashes is that the
76. cam and reset cam on the cycle shaft To the right is the operation shaft with the shock release clutch carrier return clutch and pinion tab governor and pinion space and back space clutch and cam and carrier return and index clutch and cam The shift mechanism is on the right end of the operation shaft that 13 control circuits from the computer would be re quired to control the type writer However when the typewriter is typing a char acter only the seven type element control functions R1 R2 R2A R5 T1 T2 and CK trip the cycle clutch and SH shift may be quired at the same time The next five functions SP space BS back space CR carrier return IND index IBM for line feed and TAB tabulate do not need any of the type element control functions This allows a line saving multiplexing scheme to be used As shown in the circuit diagram Fig 1 the CK line that is always on when a character is being typed is used to control the electronic equivalent of a six pole double throw switch When CK is on the type element control functions are connected to the computer When CK is off the non printing functions are con nected The shift function must not change during a character typing operation and is pro vided a control line of its own so that it may be controlled separately from the other functions With this interface cir 23 cuitry all of the functions of the typewriter ca
77. carried my TRS 80 with me to San Jose to Dallas and back home I sure wouldn t have done that if it had been in a metal case What other computer sys tem can you throw in a suitcase and take with you Byting the Apple Since they were giving out free copies of Byre at San Jose I stuck a copy in my flight bag to bring back The price was just right On the flight had the choice of sitting back and resting or reading the magazine I made the wrong choice and soon got a men tal hernia over a review of the Apple II by editor Helmers Before reading the Helmers view of the Apple I had the im pression that it was an excellent system Many of the computer store owners I have talked with were very enthusiastic about it and it seemed to be one of the best selling systems on the market possibly giving Radio Shack and Commodore a run for their money The reader comments in the letters had all been very posi tive so I was unprepared for the vicious attack in Byte Helmers who I understand got the Apple free may provide an object lesson for manufac turers who are feeling generous He apparently could see no good in the contrivance He didn t like continued on page 106 EDITOR S REMARKS Who Reads Kilobaud Magazine We not only have a reputation for being a magazine for begin ners in this field we flaunt it I think we need to sit back and ex amine just who these begin ner
78. ce of attrac tive solid oak or walnut cabinets that enhance any home or office The 85 P gains its efficiency in program preparation and code execution from the increasingly popular PASCAL language The 85 P provides the full PASCAL environment including 700 Ipm compiler interpreter random and sequential files a screen oriented editor interactive source linked debugger plus full documentation and a 90 day war rant y The complete system costs 7495 Delivery is quoted at 30 to 60 days with Northwest Micro computer Systems paying for de livery on any order shipped later than 60 days A variety of options is available Northwest Microcomputer Systems Inc 121 E lith Eugene OR 97401 Byte Size Breadboards from CSC The age of LSI has put a lot of power in Lilliput for users of Continental Specialties Corpora tion Experimentor Socket solder less breadboards This seems es pecially true for the palm size EXP350 and 650 Each is just 3 6 inches long The EXP350 offers 3 inch center spacing to o The 650 accept standard DIP packages the 650 offers the wide 6 inch spacing appropriate to wide LSI DIPs Their small size offers the perfect opportunity for byte size modularity This can happen in several ways A complex LSI function IC like a UART for example can be ac commodated along with perti nent support discretes and con necting cables as a mo
79. computer all you have to do is provide solenoids to control the latches Similar solenoids can control the clutches for space back space carrier return line feed tab and shift My Selec tric had all of the solenoids except for the shift If yours doesn t and you have a little mechanical ability you should be able to add sole noids made from old relays Before you start be sure to get a copy of the service manual for your typewriter Manuals and repair parts can be obtained through your local office or through an Parts Distribution Center which major centers like Dallas provide 24 hour service at fair prices How Many Control Lines There are 13 Selectric functions so it would seem SHIFT MJE 340 SOLENOID 7 Lg 48y 5 Ti CR SAME CIRCUIT TO DRIVE OTHER SOLENOIDS _ 4 1 4 7400 CA2 IN 4007 R5 17 VAC Fig 1 Interface circuit diagram me x n mi i Teen Photo 2 The type element is visible on the carrier The carrier rides on the print shaft which is driven by gears on the left side The 11 inch platen has pins for paper drive s ns 1 am voy Kr n 47 D 5 11 Photo 3 The belt drive is in the center of the photo To the left of the drive pulley are the cycle clutch five unit cam selector
80. could be used but an unusable tape I O port would result universal asynchronous re ceiver transmitter UART hex inverter integrated circuit Baudot clock and 60 mA loop circuitry are required to com plete the interface sche matic and parts list for this out board circuitry are given in Fig 1 and Table 1 respectively The baud rate potentiom eter R2 should be adjusted to a frequency 16 times the tele printer baud rate If the tele printer has 60 wpm gears the clock rate should be 727 Hz if the machine has 100 wpm gears the baud rate clock should be adjusted to 1187 Hz Table 2 shows the connec tions that must be made be tween the interface circuitry and the H8 2 parallel I O con nector The parallel 1 0 cable is wired as recommended by the H8 2 parallel I O manual for the H10 tape reader punch Finally the jumpers on the parallel I O channel should be configured Wire Color White Black White Brown White Red White Orange White Yellow White Green White Blue White Violet White Gray Red Black Red Yellow Red Green White Black Red Pink Tan White Gray Violet Blue Green Yellow Orange Red Brown Black i EE wat Table 2 H8 2 to UART interface CHARACTER CONVERSION FIND BAUDOT FROM TABLE USING HL FOUND SPECIAL CHARACTER PRINT LEFT PARENTHESIS icco PRINT NO AZ VES RIGHT 4 0 ow Um cco UART Interface Pin 11
81. d in tackling a major programming package would do well to register with us This could prevent ten programmers from working up very similar dental programs for example Tell us what you are planning to put together and we ll let you know if anyone else is working on something similar Packages will be chosen on the basis of excellence not first come Very Rich Programmers We feel it is in the interests of the whole industry that program mers get a major piece of the ac tion The ability to sell micro computer systems rests on the ex cellence of the programs more so than the hardware so why not make it possible for programmers to benefit accord ingly Our system should make it possible for programmers to get rich beyond their wildest dreams Suppose we come up with a hot moving van package and sell it for 995 to the customer This would wholesale to the dealer for 597 40 percent off The rep would get 10 percent leaving a net sale of 537 30 Twenty percent of that would come to 107 46 If only 10 per cent of the van firms bought the system this would net the pro grammer 859 680 before taxes I suspect that sales will be more like 75 percent of the industry than 10 percent but why build the pie factory in the sky A 75 percent sale would bring in about 6 5 million in royalties Is 995 a little high for such a package The customer would be buying about 15 000 or so in hardware to go along w
82. d the code conversion and 1 O information especially inter esting since my current project is to interface an EBCD Selectric Data Terminal to my SOL There is hardly a page in this book that does not contain at least one example program with source and object coding plus flowchart These examples are really subroutines that you can use in countless programming situations A partial list of these subrou tines might include checksums finding a given ASCII character changing the parity of a string of characters ASCII to decimal conversion addition subtrac tion multiplication division sorting indexing a table code conversion and so much more In fact the emphasis in chapters 5 to 12 is on subroutines that can be combined to form more complex programs Chapters 13 to 16 tie together everything you have learned This is the dessert course My assem bly language programming tech nique always started with coding after some sketchy mental prob lem definition Dr Leventhal has convinced me that this is wrong Problem definition and program design should come first fol lowed by coding debugging test ing documentation mainte nance and redesign Introduction to assembly language programming Assemblers 8080 8085 instruction sets Simple programs Simple program loops Character coded data Code conversion Arithmetic problems Tables and lists 10 Subroutines 11 Input output 12 Interrupts 13
83. d time and without a doubt that is the most important part Admission will be free for buyers Sellers can drop me a line continued on page 110 AROUND THE INDUSTRY The following is from an official bulletin issued by the Santa Maria CA Police Department The DataSync Corp was start ed in early 1977 by Colonel David Winthrop and advertised exten sively in the national computer magazines In late June 1977 Santa Maria CA Police detectives learned that Colonel Winthrop had used other names and had obtained driver s licenses under at least three names Police learned that the Colonel had de frauded a Santa Maria man of John Craig pretense thefts amounting to a quarter of a million dollars in five different states within the past four years other local state and federal agencies declined to pros ecute him On February 26 1978 Hunt who had been serving his term at Chino State Prison escaped from a minimum security facility Hunt is currently being sought by California authorities Hunt is a white male 6 3 220 pounds with reddish brown hair and hazel eyes He has worked as a TV repairman and has run busi The many faces of Norman Henry Hunt Jr AKA Colonel David Winthrop 10 000 under the pretense of designing a computer board for him and detectives obtained an arrest warrant for Winthrop along with search warrants for his home and his business Winthrop was ar
84. dule on a CSC 650 An LSI function can be synthesized with less com plex circuitry A counter decoder and display for example can be combined on a single EXP350 and treated as a unit as can a data converter an interface cir cuit or any of a number of func tional modules CSC s EXP350 is priced at 5 50 unit the 650 at 6 25 Continental Specialties Corpo ration 70 Fulton Terrace New Haven CT 06509 REX Computing System RCC introduces REX the total microcomputer system ful ly assembled complete with a Z 80 CPU 24K of RAM video output system keyboard a microfloppy disk drive featuring double sided recording cabinet and power supply The REX system includes an S 100 motherboard containing the CPU video display interface bootstrap and Monitor PROM and powerfail and vectored inter rupt circuitry The system comes complete with a modern walnut sided cabinet and a 15 Amp power supply and includes space for a second microfloppy drive plus five slots for S 100 bus options A complete line of low cost software options is available These include ANSI FORTRAN IV with subroutine library and 8080 and 7 80 extensions includ ing advanced math and string handling functions floppy disk operating system file manage RCC s REX Microcomputer GRI Model 756 keyboard ment system text editor and linking loader RCC offers a wide range of op tions for the REX system in clud
85. e segment It s now 07 02 22 and time to check pulse rate for six seconds while counting the beats Then miltiply the pulse count by ten in order to get the rate and begin another two minute countdown 07 02 37 Let s see add ing two minutes gives 07 04 37 It s really not all that complicated until you try it while concentrating on the exercises thought that programming our microcom puter to assist in timing and pulse rate determination would be an interesting ap plication Here is the result Exercise Program Functions The program listed pro vides the functions of 1 Reviewing the major con cept of utilizing pulse rate as an effectiveness indicator 2 Displaying the exercise se quence 3 Calculating and displaying your training pulse rate based on your age 4 Displaying that segment of exercise sequence to be ac complished next 5 Timing each segment while displaying segment elapsed time on a video display in five second increments 6 Indicating when pulse rate determinations should be made 7 Accepting 15 pulses that correspond to heartbeats and crease or decrease in the rate of activity including taking a break Timing of any recom mended breaks is auto matically accomplished and acting as a frequency counter calculating and displaying your pulse rate 8 Interpreting that pulse rate and recommending RUN EXERCISER THIS PROGRAM PROVIDES THREE FUNCT
86. e a working system BM PHOLD ES Ww CENE 2 80 25 BUSRQ 5V PRDY 2 80 PIN 24 WAIT 5 PRESET PSYNCA 2 80 9 D5 2 80 23 BUSAK 2 80 PIN 27 2 80 26 RESET 2 80 PIN 27 MI 20 T SEE TEXT C26 PHLDA C 088 Fig 2 S D Sales CPU card the most powerful 3D software yet for your 8080 and 280 Re 10 projection modes 500 lines second interfaces to any S100 display device Uses 8K memory Only 30 for Tarbell tape and documentation MATROX interface program included Write to us for more details and a complete catalog o 8080 280 6800 and BASIC graptvc systems T LOGIC V Culver City 90230 549 RO CHE Systems MULTI CASSETTE CONTROLLER BOUI CASSETTE 232 217 Read and write records from and to up to 4 cassette recorders with one Tarbell Cassette Interface e Included software handles Assembly Language and BASIC e Much more software available Find out by writing for our free brochure Ask about our complete line of data processing supplies Distributed by ELLIAM ASSOCIATES 24000 Bessemer Street Woodland Hills CA 91367 NOW HEAR THIS DISPLAYS ARE HERE 946115 in dispays 0 through F e Built in latch and leading zero blanking eUse 6 modules to display hex address and data e Connect 2 modules to an
87. e covered all the book s good points but none of its bad ones That is probably because I couldn t find anything to criticize My only negative reaction has to do with 8080A 8085 Assembly Language Pro gramming having been advertised as available in October 1977 which is when I ordered and paid for it it was actually not printed until late January 1978 which is when I received it In my opinion 8080A 8085 Assembly Language Program ming is a worthwhile text and I m hoping for 7 80 version soon If my technical library had to be reduced in size for some reason this is certainly one book I would keep on the shelf Rod Hallen Tombstone AZ Simplified BASIC Programming Gerald and Joan Silver McGraw Hill New York 1974 12 85 Simplified BASIC Program ming is an excellent text for those of you who have absolutely no ex perience in computer program ming and occasionally need to look up the definition or applica tion of an instruction Simplified BASIC Programming is an excel lent reference manual The first section of the book is devoted to an in depth explana tion of the operation of a time sharing system For those of you who have access to a time sharing system this section is invaluable For the microcomputer owner this section may be skipped as your system probably operates in a substantially different manner The second section describes in easy to understand language how most of the instruct
88. e it was originally hoping to charge American Ex press for its services Beware Master Charge Visa Carte Blanche et al Consumer Computer is ready to pounce wherever and whenever you make the slightest error by slipping a loose bit in your overgrown com puter frame Joseph Roehrig Middle Village NY Trouble Trouble This letter refers to the article Tiger Trouble p 106 in the March 1978 issue Although the calculator used was not identi fied I have assumed that it is either an SR 52 TI 58 or TI 59 The program as printed on p 108 contains errors in syntax es pecially on line 72 which calls for a function not directly executable on these machines within the number of steps allotted and on line 63 where no error halt at a flashing 9 999 999999 99 will occur at least on the 58 59 unless an R S is provided or flag 8 is set Furthermore even after all syntax is corrected for the TI 59 this program will not yield the expected result with a seed of 0 9 given on pp 108 109 I suggest that in future articles on TI calculator programs you specify the calculator model for which the program is intended and that you provide a copy of the PC 100A program listing printout so that no ambiguity in interpretation is possible David P Leising Grand Rapids MI It is an SR 56 program and I apologize for the omission John Defective Formula In the December 1977 Kilo baud
89. e passersby had already filled in a card indicating a high percent age of show goers coming back for a second and third day to see the exhibits Though it s possible that a few people managed to see the show and not get near the Kilobaud booth this is unlikely Our count on the filled out cards after sort ing out the duplicates some peo ple try to increase the odds on these things came to 4100 A check with several exhibitors who were handing out literature indicated that some had handed out over 3000 pieces others claimed close to 5000 Software Needed I don t think there was one manufacturer or dealer who didn t express the universal cry for programs Hobbyists have been spending a lot of money on hardware but so far there has been very little they could do with their expensive systems except play Star Trek Submarine Mastermind and so forth The Kilobaud plan for dis tributing software was enthu siastically embraced by every now all we have to do is get it going We do have the staff and the equipment to get this project running so I hope the first programs will be coming out in the next few months Programs for the TRS 80 and PET will be out on cassettes We have a first rate lab for checking out pro grams a superb cassette duplica tion system for bulk production of cassettes the publishing facili ties for printing documentation the sales force and list of dealers to distribute
90. e socket If other Z 80 circuit boards output the machine cycle state M1 on bus line 005 S 100 bus line 39 dur ing PSYNC it may be necessary to disable this feature in a similar manner Otherwise attempts to load memory from the front panel may result in errors in bit 5 as two Tri state devices fight each other for control of that bit Construction Because of a fortuitous cir cumstance low price and availability my front panel was constructed on a large pro totyping board with excellent ground and power buses Either this sort of board or an S 100 prototyping board is recom mended If the S 100 board is used you can simply take a standard aluminum chassis of appropriate size mount the desired number of S 100 edge connectors on top of the chassis hand wire the connec tors together and place the front panel board in the for wardmost edge connector The pin connections on the diagrams reflect S 100 bus signals A PC board is really not very practical It would be tedious to design and would not be suited for the inevitable modifications that home brew enthusiasts are prone to make Wire wrap and wiring pencil are the two techniques usually employed used the latter Layout is by no means critical and actually used no bypass capacitors ex cept for 50 uF electrolytics at the points where Vcc entered the board However good prac tice according to Don Lan caster s TTL Cookbook calls for one 0 01 to
91. ed for either shift up or shift down 1 15 second or 67 milliseconds Space and back space are also done in half a revolution of the operational shaft but with a difference The cycle and shift clutches are wrap up spring clutches and take hold almost instantly The space back space carrier return and line feed clutches sprocket and dog clutches the sprocket having nine teeth This means that there is a 1 9 operational shaft revolution time uncertainty or 15 milliseconds in the time for these functions For this reason the space and back space functions are allowed 81 milliseconds Line feed requires a full turn of the operational shaft and gives a time of 148 milli seconds when the clutch un certainty is added The time required for carrier return is dependent upon how far the carrier has to travel allowed 525 milliseconds for the carrier return enough for an 80 character line Where Do You Plug It In There are ten wires going to the typewriter eight for typing functions one for the power relay and a common ground These connect to an MC6820 peripheral interface adapter PIA in the com puter the eight control lines to the data output PIA terminals and the power relay line to the CA2 terminal Then the computer only has to put the proper outputs to the PIA to control the type writer thought the easiest way to interface the typewriter to the program requiring hard copy output would
92. ed money 330 kit 365 assembled PO Box 2507 Santa Maria CA 93454 Oh yes the chess tournament What crowd wasn t able to follow the action but it was sure there My friend Doug Penrod inset played a big role in getting this event going through his Computer Chess newsletter which will be a feature in Personal Computing magazine in the future meca 2 3 L ul It never fails At almost every computer convention you have at east one person go berserk and try to hit master reset and crash a system guess the strain was just too much for Nancy Millikin and I sure hope she felt better after hitting that but ton On the serious side if you d like some additional info on Meca s fantastic mass storage system with a voice prompt and response capability write to them at PO Box 696 7026 Old Woman s Spring Rd Yucca Valley CA 92284 Ask for their mass storage buyer s guide 2 iit Il Hl 1 Wanna draw a crowd Put up Digital Research sign don t know whether you ve noticed it or not but there are two pieces of software playing a dominating role in this microcomputer indus try Microsoft BASIC and Digital Research s CP M Operating System Heck you can even get CP M for the North Star drive Lifeboat Associ ates 164 W 83rd St New York NY 10024 and for the ICOM Frugal Floppy Computer Mart of New Jersey 501 Rt 27 Iselin
93. em aren t much of a mystery or a fascination No I ve always been amazed at the tremendous cost of such systems and knew it was just a matter of time before some enterprising micro enthusi asts came along and developed one we could all buy Well it s happened Let me tell you about In last month s editorial I gave you an introduction to what the folks at The Micro Works are up to They ve been building S 50 6800 boards for some time now they have an EPROM Program mer PROM board Universal 1 board and extender boards but their latest is really some thing They have developed a digital video system called the Digisec tor which interfaces an inex pensive TV camera with a South west Technical Products 6800 system The TV image is convert ed by the Digisector board into Photo 5 Andrew Phelps senior programmer a high resolution digitized pic ture and stored into the computer s main memory So far so good and up to now things have been quite inexpen sive the cost of an SWTP 6800 system a 200 to 300 television camera a video monitor for 150 170 for the Digisector board and a terminal for the computer Not too bad right Now we re going to have to spend a few bucks for a good high quality printer and the Micro Workers feel the Malibu 160 is the best for the job and from what I ve seen I ll have to agree catch the review on that printer in this month s
94. embly Language Programming by Lance A Leventhal I use assembly language in situ ations where BASIC won t do the job such as graphics input output or where BASIC pro grams won t fit due to memory size limitations In addition to the usual I O operations keyboard printer and video turn various external devices on and off under computer control This requires being able to manipulate CPU registers addresses and data lines it takes assembly language programming to do this I have written many programs but after skim reading this book I realized that have missed the significance of or misused many 8080 instructions A second more thorough study confirmed this and contributed greatly to my assembly language programming ability Table 1 is an outline of the con tents of Leventhal s book Just about every possible question that you could come up with is answered in one or more of these chapters Chapters 1 and 2 serve as the appetizer a comprehen sive discussion of assembly language programming and as semblers Chapter 3 does more than just list the instructions with a brief description a half page or more is devoted to each instruction and explicit examples promote better understanding Nowhere else have I seen the 8080 instruction set explained with such detail and clarity Chapters 4 to 12 are the main course they take you from the simple program through every conceivable CPU operation 1 foun
95. er con trol of typewriter on off single or double spacing all capitals or upper and lower case letters and automatic page formatting This was to be done by means of non printing control characters as will be explained in part two The Mechanical Marvel The Selectric typewriter is a mechanical marvel or night mare depending on whether it is working right or you are trying to understand how it works and repair and adjust it The basic typewriter is entirely mechanical except for the electric motor and switch The characters are selected by tilting and rotating the ball typing ele ment to get the proper char acter in position and then striking the ribbon and paper with it The sequence of events goes something like this The motor drives a pulley through toothed belt which drives the opera tional shaft on the right side of the machine A series of clutches and cams on this shaft performs the carrier return line feed tab space back space and shift func tions more about this later The pulley also drives the cycle shaft on the left through a clutch on the pulley The cycle shaft drives the filter shaft and print shaft through gears and does the print function When you press a key an interposer is pushed down so that it trips the cycle clutch to start the print mechanism It is also positioned so that blade on the filter shaft strikes it and pushes it for ward The interposers a dif ferent
96. f the above manufacturers for con sideration at this meeting Photo 1 The complete Micro Works Malibu system Intertec s SuperDEC pull out the guts amp screw in the brains Nhile we ll admit the difference in ap pearance between the DECwriter 1 and sur new SuperDEC is difficult at best to the difference in performance is as tounding The SuperDEC is our new Throughput Optimizer designed to be installed your existing JECwriter 11 teleprinter Not only nur SuperDEC Optimizer increase the speed of your DECwriter ut The SuperDEC Optimizer is designed to replace the digital electronics in your existing DECwriter Il In less than five minutes your DECwriter can be trans formed into a SuperDEC The Super DEC Optimizer is completely plug PR compatible with the cables in your pag pens its original pos dit DECwriter The only installation tool REEF yo peior required is one that we give you a tures ve E ert L screwdriver Just pull out the guts and OE M screw in the brains No special technical XECwriter until now 2 fx Pa skills are required And if you get bored You ve undoubtedly phe dy heard c watching your DECwriter print faster SuperTerm B than you can read the old digital elec eleprinter that has been tronics may be reinstalled in a matter of JECwriters by the thousands 4 1 minutes It s really just that sim
97. gh outline of what they are selling This is tremendous pro motion for microcomputing The airline magazines are run ning a special computer section in June so keep your eyes open if you are traveling to NCC or the Atlanta Hamfest Computerfest The Second Faire The San Jose Computer Faire was enjoyed by just about every one It was packed with people and there were many more pro spective exhibitors than space for exhibits Many exhibitors mentioned that there seemed to be a lot less room than there had been last year at San Francisco room for fewer exhibits and tiny aisles which quickly filled up making it very difficult to get around A check with a Convention Facilities Directory showed us that San Francisco had 37 000 square feet in the main room and 30 000 more in the two side rooms for a total of 67 000 square feet The San Jose hall had only 30 000 square feet plus about 2000 more for the micro booths in a separate room No wonder it seemed so crowded it was half the size of the San Francisco Civic Auditorium A rough calculation of the aisle space showed about 11 000 square feet When a density of one person per ten square feet is reached an exhibit hall is generally considered full and it is difficult for people to move around This leaves room for elbows and a bag of literature but not much more At times the show reached this density in the more popular spots indicating a p
98. ght it will compliment you and then go on with more instructions If you goof the tape will rewind and re play the part you screwed up How far in the future is all this Jolt had just such a system up and running two years ago using a Sony video system and Jolt microcomputer Prices on video recorder systems are coming down performance and availability are going up These would seem ideal mates to our computer systems And think of the data storage on a video cassette Jolt was recently bought out by MOS Technology Commodore so we may see some of this technology coming along sooner than we think if Commo dore lets the Jolt crew have a free hand Speaking of the PET After the Faire Sherry and I stayed over a couple of days in the San Jose area We made a visit to Extensys and then went over to Commodore to see the 7 B E 88 22 TM What about Radio Shack On the way back from San Jose we stopped off in Dallas Fort Worth The next day we had lunch with Bill Mueller of ICOM and Art Housholder of AGL Electronics in Dallas A Mexican restaurant right near AGL was fantastic I don t care if AGL wants to throw away their advertising money like drunken sailors in other maga zines 111 be stopping by to visit at every opportunity From there we waddled on to Radio Shack and Siegel Despite a broken leg gained a On the right of the PETs being checked
99. her options 1 000 00 creativity prize You can also add 1 000 00 to your bank account as a reward for your inventiveness Just write an article on an original Bit Pad application and submit it to any national small computer periodical If the editors publish it and the decision is solely theirs Summagraphics will pay you 1 000 00 Contact Summagraphics for rules concerning this offer and OLAS U1 eae gt nm 4 rd 11281111 35 Brentwood Ave Box 781 Fairfield CT 06430 548 Phone 203 384 1344 TELEX 96 4348 31 A Strategy for Healthy Living This computerized exercise fitness program provides a systematic approach to getting then staying in shape Al s exerciser program has laid the groundwork for some really ex citing possibilities The next step is to have an analog to digital pulse counter so the computer can monitor the pulse continu ously And along with that speech output so the computer can tell you as you exercise if the pulse rate is high or low John Gerbens 1038 E 6th Pi Mesa AZ 85203 the process of surviving that ordeal known as a physical examina tion was introduced to a 10 INPUT HOW MANY DATA POINTS DO YOU HAVE W 20 FOR Z 1 TOW 30 ENTER THE NUMBER OF BEATS FOR POINT Z 40 INPUT X Z 50 ENTER THE VALUE OF T FOR POINT Z 60 INPUT Y Z 70 NEXT Z 80 DATA ENTRY COMPLETE 90 FOR Z 1 T
100. however they stress keeping the hardware simple and exercising control by software I appreciated most of the simplified no mystique ap proach to several things that had long bothered me among these were flag testing the use of status words and the inside working of the many conditional branch in structions The entire instruction set is covered in greater detail than had previously encoun tered It is methodically consid ered by function by grouping the related logical operations for example and whole pages are devoted to illustrating certain in structions that might be consid ered tricky or difficult The use of octal may disap point some readers The explana tion is that the 8080 instruction set was designed this way Logical operations all begin with 2 in oc tal and MOV instructions with 1 The accumulator is 7 and the memory 6 Thus MOV A M and 12 MOV M A are 176 and 167 re spectively much easier to remem ber than two dissimilar hex codes The book s overall theme is that the microprocessor is a use ful tool No mention is made of high level languages games or heavy number crunching the in terfacing is to practical devices and the programs are in simple machine language all designed to do something And although the special 8080 support chips are all covered in some detail TTL alternatives are explained where they can be applied It is difficult to classify this as either a hardwa
101. iate bus With no other device in the system power up the front panel It should draw about 1 ex E e lb B Amp at 5 V dc depending how many LEDs are illu minated With a voltmeter check the enable pins of the Tri state buffers of the address and data out buses These pins should be in the disabled or AO 79 802 8 Al Fig 1 Front panel high level If this is the case then it should be safe to plug in the CPU and memory cards Be sure to remove power before inserting these cards and bear in mind that the commercial boards require 8 V dc un gt A4 552 AS 292 6 822 A7 832 as 842 A9 ED 577 You can now perform a quick checkout and run a simple pro gram at the same time The pro gram will add two binary num bers and store the result in a E Heo ss si eh 1 SG 2 amp 4 S poo N CI a EIE REE we HERE memory location where it can be examined 1 Set DMA switch to DMA mode and SINGLE STEP switch to CONTINUOUS mode It may be necessary to activate the RESET switch to get a DMAG 30 007 lt 40 006 391005 15381004 9 1003 88 002 C35 00 C36 000 H 2 4 4 4 4 9 E 4 gt IM 016 PY Q m gt 02 392 015 nude m 222 Pt C 91 014
102. ing b amp w or color video monitors rf modulator genera tor expansion microfloppy drives RAM memory to 64K on the motherboard no bus slots needed a 120 cps 80 96 column printer programmable serial communications channel and a data communications modem The REX system lists for 2495 assembled and tested only Realistic Controls Corp 404 W 3Sth Street Davenport IA 52806 New Model 756 Full ASCII Keyboard The Model 756 keyboard from George Risk Industries provides encoding for all 128 ASCII char acters and control functions im posing no limitations on software design or hardware capability Utilizing reliable IBM series key switches and low power MOS en coder circuitry Model 756 is de signed to bridge the gap between basic keyboards and expensive custom OEM models Assembly and mounting are simplified through OEM industrial grade components and a rugged MIL grade printed circuit board The durable circuitry is complement ed by custom molded keytops and a line of heavy gauge steel en closures for desktop use The 756 s complete line of ac at 3 cessories includes a numeric pad custom cables and connectors The versatile interface allows user selection of parity positive or negative logic data and strobe outputs alpha lock operation and both dc level and pulse strobe signals A latching shift lock key is included and all outputs are TTL DTL MOS compatible Kit is 64 95 assemb
103. inter and we have a review of the Malibu 160 in this month s issue One of their largest dis tributors is Jade Computer Products Drop a line to Jade for more info There seems to be an abundance of S 100 disk systems hitting the market right Well in the course of shopping around be sure to look over the capacity and software being offered with the Micropolis MetaFloppy and MacroFloppy drives Their Extended Disk BASIC has file management and programming capabilities and they also have a 16K DOS 7959 Deering Ave Canoga Park CA 91304 SMOKE SIGNA If you 6800 owners haven t checked into the line of SS 50 bus products from Smoke Signal Broad casting then you re missing the boat They have a DOS that supports from 1 to 3 of their miniflop pies patches for SWTPC BASIC and a co resident editor assembler They also have a 16K static memory board 529 and more PO Box 2017 Hollywood CA 90028 us The Digital Group was demon strating a graphics system that made a lot of mouths water There he is folks The man be hind the CP M Users Group Tony Gold Drop him a line they ve got twenty four vol umes diskettes in the library at this time 164 W 83rd St Here s the group from ALF Greg Bloom Philip Tubb did you catch his Incredizing article the April issue and Tim Gill If you re into com puter generated music these folks have some top notch boards for the S 100 bus
104. ion The questions and answers both have a nice balance of simplicity ac curacy and amazingly enough realism and actually convey the continued on page 111 Radio Shack s personal computer system This ad just might make you a believer TRS 80 Breakthru TRS 80 microcomputer 12 video display Professional keyboard e Power supply e Cassette tape recorder 4K RAM Level I BASIC e 232 page manual e 2 game cassettes You can t beat the 4K system at 3599 or the step up 16K system at 899 TRS 80 Sweet 16 e Above except includes 16K RAM or the fast 4K printer system at 1198 TRS 80 Educator e Above except includes 4K RAM and screen printer Orthe Level ll TRS 80 Professional 16K printer disk Above org Me system at disk drive expansion interface and 1 BASIC 52385 So how you gonna beat the system that does this much for this little No way The amazing new 32K Level Il 2 disk line printer system at line printer 3874 amid a and two disk drives Get details and order now at Radio Shack stores and dealers in the USA Canada UK Australia Belgium Holland France Japan Write Radio Shack Division of Tandy Corporation Dept C 051 1400 One Tandy Center Fort Worth Texas 76102 Ask for Catalog TRS 80 Radio haek Prices may vary at individual stores and dealers The biggest name in li
105. ions are used I say most because in 1974 BASIC was not as sophisticated as it is today Examples of the use of each instruction or combina tions of instructions are clearly stated At the end of each chapter a review and a quiz are provided The last section of the book contains example programs with complete documentation and a description of the way the prob lem was solved This book is a good reference for those of us who can t seem to remember whether a comma or a semicolon is necessary to print closely spaced output or any other syntax problem that may drive you to the brink of insanity Although Simplified BASIC Programming is available through any bookstore you may find a used copy for sale at sub Stantial savings at your friendly neighborhood college bookstore And if you are really watching your budget you may find Simplified BASIC Programming along with other informative reading on BASIC at your local library Jim Cambron Topeka KS The 8080A Bugbook Rony Larsen Titus Howard W Sams amp Co Inc Indianapolis IN 9 95 paperback One book out of a hundred makes you wish you had seen that one before slogging through the other ninety nine This is such a book It should be subtitled You Wanted To Know about the 8080 and Its Support Chips but Didn t Know Where To Look In the Bugbook tradition the 8080A neatly balances theory and practical example It comprises eight chapters with
106. it was introduced years And sales have increased as fast as production But now we re pulling out all stops MOS Technology is now a Com modore company And Commodore knows how to produce quantity without sacrificing quality This is the KIM 1 Important Inquiries from a select number of dealers will now be considered 8 KIM 1 is guaranteed Not just for parts the entire board for 90 days At no charge commodore So call or write to us now KIM Sales MOS TECHNOLOGY a commodore company 950 Rittenhouse Road Norristown Pennsylvania 19401 Phone 415 666 7950 in Canada KIM Sales Commodore Business Machines Ltd 3370 Pharmacy Avenue Agincourt Ontario Canada M1W2K4 Phone 416 499 4292 For Overseas Applications KIM Export Commodore Business Machines 901 California Avenue Palo Alto CA 94304 Phone 415 326 4000 KIM is a reaistered trademark of Commodore International Ltd and the Commodore companies to describe microprocessor boards and systems a y The French Do It Again A letter from W3NET included a reference from a navy published book and it covers the history of Teletype codes The upshot of all this is that the five level code we ve been using all these years is not Baudot at all it is the Murray code developed by Donald Murray around 1901 The Baudot code is entirely different though still a five unit code For instance in case you do
107. ith it so it would really be miniscule running less than 25 a month What about my plan for 7 95 software Oh we ll have a lot of that The programs for games for homes general programs teaching programs these will be of interest to much wider interest groups and we can look for sales in the millions of these programs Most of the TRS 80 and PET programs will come in this cate gory at least until the hard ware is available for business use of these systems Are you still reading and not rushing to your computer to pro gram You need some All Bran badly The Kilobaud Lab As soon as the TRS 80 and PET are brought into the system we ll have one of the most exten sive microcomputing systems anywhere On line at present are two Altairs an Imsai an Ohio Scientific Challenger a Heath H8 H11 and five Compu colors Peripherals on line arc a Centronics 51 printer a G E Terminet a Teletype an OSI disk two Altair disks a North Star disk the H10 and the SWTP CT 64 a Computalker a clock module the Heuristics board an S D Sales Z 80 etc Barry our tech is working to 1 all of this to our Prime mini computer system as well as the TRS 80 and PET This will enable us to check out submitted programs on just about every thing popularly available lacking only a 6800 system In addition to our wanting to know personally how all the vari ous systems work another reason for all
108. king for big trouble The reason is simple The worst case low level output voltage for gates of the 7400 family is 4 volts for 74LS family it is 5 volts Fast silicon diodes like those of the 1N444X family at a forward current of 1 mA have a static forward voltage of maximal 55 volts these figures come from the TI manuals If now the output of a TTL gate is driving the input of a fol lowing gate via a decoupling diode the low level input voltage for this gate can be 5 plus 55 or 1 05 volts or even higher depend ing on the size of the pull up resistor The maximum permis sible low level voltage for all devices of the 7400 and 74LS series however is only 8 volts That means this arrangement operates in a voltage range that is outside of the manufacturer s specifications The circuit may work sometimes and then it may not work depending on the whim of the ICs power buses tempera ture and phase of the moon That s the reason diode logic with TTL devices having a nor mal totem pole output should not repeat not be used unless maybe you are using hot carrier diodes which have a lower for ward voltage but are very expen sive or germanium remember germanium diodes which are slow Erich A Pfeiffer Granada Hills CA Ralph Burhans Reply The critique of Wired OR is perfectly cor rect in stating that use of diodes in series with normal totem pole TTL output
109. le cursor Switch selectable features in clude black on white or white on black blinking or nonblink ing __ cursor and variable baud rates No software is required The Naked Terminal can be config ured by DIP switch to drop into an existing system replacing the serial I O card and stand alone terminal without making any changes to software The Naked Terminal is a com plete dumb terminal on an S 100 board It contains a microproces sor with its own memory its own software drivers and its own in ternal bus It won t take up any of the 64K memory address space of the S 100 bus Like all Dynabyte products the Naked Terminal is completely assembled socketed tested and burned in Dynabyte s guarantee is for a full year the longest in the industry Dynabyte Inc 4020 Fabian Palo Alto CA 94303 b 2 2 4 2 4 2 4 gt 4 pi 2 2 2 1 Dynabyte s Naked Terminal 8085 PASCAL 85 P The new 85 P programmer s workbench from Northwest Microcomputer Systems Inc combines the throughput of the 3 MHz Intel 8085 and the power of PASCAL The standard system features 1 8085 CPU with 54K bytes of static user RAM 2 one mega byte of storage in two double density Shugart floppy disk drives 3 24 80 high resolution display with 103 station Hall ef fect keyboard 4 two serial ports for printer and second terminal or modem 5 a choi
110. le quantities to 435 each for orders of 100 Innotronics Corporation Brooks Rd Lincoln MA 01773 Printer Interface for Apple Microproducts has announced a printer interface for the Apple computer which is compatible with the Southwest Technical Products PR 40 Printer It will be marketed as a preassembled PC board that plugs directly into the Apple computer an intercon necting cable and a cassette con taining the operating software The printer prints one line at a time when the return key is struck The printer subroutine can also be called in BASIC to print the entire contents of the video screen While in the BASIC mode using the list subroutine the printer will continually record the program while the video screen scrolls up one line at a Microproducts interface with Apple and PR 40 CSD s Microdesk time The complete plug in inter face with software sells for 49 95 Microproducts Dept K 1024 17th Street Hermosa Beach CA 90265 Microcomputer Storage System The Computer Systems Design Microdesk is a new addition to Kilobaud s microcomputer lab We ran a release on the Micro desk in November 1977 now we ve had a chance to utilize it The desk s ease of assembly makes for a quick and useful ad dition to any room with one ad justable shelf that you can ar range to your specific needs Be cause of its air vented design the upper shelf is an excellent loca tion for your unit
111. led and tested model 75 95 A matching en closure Model 702 is 29 95 George Risk Industries Inc GRI Plaza Kimball NE 69145 Computer related Cases The Buckeye Stamping Com pany 555 Marion Rd Colum bus OH 43207 now offers instru ment cases with keyboard holders and CRT canopies These com puter related additions fabricat ed of durable extruded alumi num are offered in standard 17 inch widths The new cases are now offered with blue or black vinyl tops with matching feature Stripes or with teakwood vinyl as an option The new Buckeye computer related cases sell in small quanti ties in a price range of 110 or 215 complete Power Supply for KIM K L Power Supplies PO Box 86 Montgomeryville PA 18936 announces the model 512 power d Buckeye instrument cases Bottom oscilloscope signals show noise reduction made possible by the Glitch Grabber supply for MOS Technology KIM users and for others need ing a 5 volt and 12 volt regulated supply The model 512 comes completely assembled and cludes a total 4 3 Amp capacity and additional 8K memory The K L power supply features 5 volts regulated with 1 4 Amp maximum 12 volts regulated with 1 0 Amp maximum 8 volts unregulated with 4 5 Amp max imum and 16 volts unregulat ed with 1 0 Amp maximum It has regulated outputs with cur rent limit and thermal overload protection fuse protected primary a
112. life and pro vision for 3K bytes of PROM The LFD 400 PROMware DOS miniDOS allows SS 50 bus owners to use their existing soft ware with simple patches This was a priority consideration in the development of miniDOS The LFD 400 uses the Shugart SA 400 drive Disk speed is 300 rpm which gives a data transfer rate of 125 kilobits per second The read write head is stepped from track to track at 40 ms per step The SA 400 drive system features a positive media in terlock which prevents door closure on a misaligned disk and write protection circuitry The LFD 400 storage media is a 10 sector hard sectored minidisk ette which accommodates 89 6K bytes of data on 35 tracks The recording technique is Bi Phase M also known as double fre quency PerCom Data Company Inc 318 Barnes Garland TX 75042 CT Terminals COMPUTER TEXTile an nounces its line of high quality hard copy hardware CT sells re conditioned QUME and Diablo daisy wheel printing terminals which feature 30 cps printers 96 character keyboards with 10 numeric pad ASCII cod ed RS 232 interface Also included are 256 charac Innotronics Series 400 floppy disk drive ter buffer user s and service manual with full graphics capa bility packaged in a cabinet with black and chrome wheeled ped estal Options include 45 cps and 55 cps mechanisms for some QUMEs other encodings pin feed platen tractor forms feeder and se
113. m s LFD 400 system trol status registers and the next 8 access the transmit receive data registers This map arrangement allows optimum use of indexed addressing in I O intensive sys tems and permits the use of a very tight interrupt polling loop The standard configuration of the 9650 is fully populated to 8 channels Prices range from 395 in single quantities to 237 at 100 A partially populated 4 channel version is also available at lower prices The 9650 is one of a family of M6800 support modules cards of the family are 6 05 inches by 9 75 inches and utilize a 43 pin dual readout edge connector with 0 15625 inch pin spacing Creative Micro Systems 6773 Westminster Avenue Westmin ster CA 92683 Disk Storage System for the SS 50 Bus PerCom Data Co s LFD 400 a minifloppy disk memory system for the SS 50 bus includes a controller PC board PROM ware disk operating system disk drive and drive power supply in terconnecting cable two mini diskettes an operator s manual and a compact enclosure to house The CMS 9650 the drive and drive power supply System components may be in dividually purchased and 2 and 3 drive systems are also available The controller board which is installed in an SS 50 bus slot of the host computer includes special low voltage drop regu lators a proprietary bit shift ing compensation circuit an in activity time out circuit to in crease drive motor
114. month and the winner will get a lifetime subscription to Ki obaud Reader service card submission is on the increase so we had plenty to draw from Winner of a lifetime subscription to Kilobaud is Fred Schild of Playa Del Rey CA Congratulations Fred Publisher Wayne Green Executive Vice President Sherry Smythe Editor John Craig Managing Editor Jonn Barry Editorial Assistants Dennis Brisson Susan Gross Administrative Assistant Dotty Gibson Production Department Lynn Panciera Fraser Craig Brown Gayle Cabana Robert Drew Cari Jackson Michael Murphy Weston Parker Noel R Self Robin M Sloan Typesetting Barbara J Latti Jennifer Johansson Marie Walz Photography Bill Heydolph Tedd Associate Editors Don Alexander Tim Barry Bob Buckman Sheila Clarke Rich Didday Phil Feldman Doug Hogg PhD Tom Rugg Peter Stark Bookkeeper Knud E M Keller Director of Marketing Daniel D Savage Merchandising Manager Robert LaPointe Area Rep Manager Cynthia Gray Circulation Rhonda Ramsey Receptionist Doni Anne Jarvis Computer Data Control Judy Waterman Judy Brumaghim Linda Cate Mary Kinzel Computer Technician Barry Bressler Computer Programming Ron Cooke Richard Dykema Steven Lionel Printing Dan Morgan Andy Comeau Mailroom Theresa Toussaint Bil Barry Sue Chandler Ethan Perry Advertising Heidi Kulish Marcia Stone Bill York European Distributor Monika Nedel
115. n be con trolled For example to do a line feed binary 00100000 or hex 20 should be the output to the typewriter To type a capital A requires shift up tilt two units and rotate left two units The typewriter then requires binary 10100111 or hex A7 If the typewriter was in a down shift condition a binary 10000000 or hex 80 would be required to shift up before sending the typewriter the A7 to type A As soon as the typewriter has started the type operation the output should be changed to 80 to hold the up shift condition but allow resetting of the latches to prevent typing string of AAAAAAAA Now if a hyphen is to be typed shift down tilt three and five right rotation are required Before typing 00 would be sent to the typewriter to 1 11 113184 y Aw MM TAM Photo 4 A view of the underside shows the seven selector solenoids at the left rear These push the latches from under the latch bail for character selection The vertical bars at the front under the keyboard are the interposers and the horizontal bars are the selector bails mentioned in the text On the right side are the five operation solenoids cause down shift Then binary 00000001 or hex 01 would cause to be typed Following this pattern you can make up a table of type writer codes for all of the characters on the type ele ment just by noting what shift tilt and rotation is needed Tu
116. n t want to believe me the letter R in Murray is 2 amp 4 In Baudot R is 3 In Murray code the uppercase R is the number 4 In Baudot uppercase R is a hyphen Convinced Murray code is also known as the International Telegraph Alpha bet No 2 It s time to change to ASCII and bury this whole mess Spadework There it was Right by the ramp leading to the United Airlines plane at Logan Boston saw this kiosk with a PolyMorphic microcomputer all set up and running It was put there by the Computer Shop of Cam bridge and must have cost a bun dle I hope it draws some business for them Just to be sure I called Bob Rivers at the Computer Shop and asked him how effective the kiosk was That s awfully expensive UBLISHER S REMARKS Wayne Green advertising so it would have to pull a lot of customers to be worth the expense Bob said that they had renewed their contract for the space if that told me anything It sure did When we were pricing displays for promoting Computermania we checked on the cost of the bill boards at the airport hoot mon They cost a couple hundred dollars a month each just for the billboards so I m afraid to even speculate what a kiosk like that runs It s located where every pas senger has to go right past it so the visibility is high There are some brochures available to help people remember the name and address of the store a rou
117. nge the article 6 In the confusion the neces sary corrections were not incor porated and one additional type setting error was added I have no Altair BASIC so I cannot supply a listing The cor rections are shown in Fig 1 Other answers to questions are shown in Fig 2 In addition to the correc tions I have attached a North Star listing of a similar game see below Thanks for your under standing Joseph J Roehrig Middle Village NY 30 FORA 1TO3 A1 A 10 FORA2 ITOIO FORA3 0TO3 105 IFA 64ORIPATHENPRINT ILLEGAL MOVE GOTO90 200 3 9 280 IFS gt A6THENM2 2 A61A6 GOTO300 320 IFM2 gt M3THENM3 M2 M4 A 392 Al INT M4 1 16 1 A2 M4 A1 1 16 1000 PRINT POSITIONS ARE FORA 0TO3 FORAI ITOI3STEP4 A2 20 A1 4 Fig 1 M M a M m b NEXTALI A Altair BASIC lets you end multi for loops with NEXT by listing the variable of the loops to be ended SS A Altair BASIC treats string variables similar to numeric values Thus Altair S 1 could mean UU and S 2 would be North Star S 1 2 and S 3 4 Fig 2 mm 10 1 5 64 3 76 88 64 76 11 DIMC9 64 8 20 FORA 1TO10NFORA1 O0TO3NREADUCA15A NNEXTA1NNEXTA 30 FORA 1TO3 A1 AKLO FORA2 1 TOLO FORAS 0TO3 40 1 2 22 16 NNEXTASNNEXTA2NNE
118. not O C could create problems in excessive zero voltage drop and is not recom mended by chip manufacturers However experimenters often do what is possible and not what is recommended particularly if the risk of failure is very small Before the widespread use of MSI and LSI many of us used Don Lancaster s technique TTL Cookbook Fig 3 18A p 146 where a 74154 decoder is used to address a diode ROM matrix with a lot of NOR intersections These work quite well and I don t recall any failures With the 74LS138 mentioned previously a two diode NOR with one pull up re sistor provides elegant simplicity driving a D input on a KIM 74LS145 with no problems in my limited experience with four or five different chips It is also correct to state that CMOS has essentially no prob lem 50 where is the argu ment The basic difference in our thinking is perhaps that adverbs like or are applied here with some judgement based on a typical case not necessarily the worst case and experimental trial 1 built my first crystal set in 1933 and also know about ger manium and use 1N69Ss if nothing else will work for a quick and dirty NOR Many computer mods where only single extra input is needed can be quickly solved with a single diode and some of ours have been working for years with no problems When designing from scratch 1 presently prefer CMOS but when modifying someone s de sign any
119. nt it is easy to use No one can match the variety of compatible DMA CONTROLLER peripherals offered by Southwest Technical The controller occupies one main memory slot Products for the SS 50 bus and the 6800 com in an SS 50 bus and uses the Motorola MC 6844 puter system Now more than ever there is no DMA controller The combination of a DMA reason to settle for less DMAF 1 Disk System assembled eee cece eee Hh 2 095 00 1 Disk System 4 2 000 00 68 2 Computer with 40K of memory assembled 1 195 00 SOUTHWEST TECHNICAL PRODUCTS CORPORATION Ad 216 W RHAPSODY SAN ANTONIO TEXAS 78216 1 KIM 1 is reliable More KIMs are in use than any other microprocessor board by thousands KIM is tried and tested honestly y 2 KIM 1 is complete 1K RAM 2K ROM Audio how man cassette and serial interfaces 0 15 bi directional TTL V lines O 23 key O 6 digit LED display All on one assembled board 3 KIM 1 is versatile Generate fixed or variable time delays under program control with the two built in interval timers O Each of the 15 lines can be used for input or output O Add a TTY with just four wires O The key pad can be mounted externally 4 KIM 1 is built with intelligence High and low level outputs are provided to interface with any type of cassette recorder The inter face will ignore voice data between segme
120. nts of digital data O Check sums or punched tape are automatically verified when make sure your next micro processor is the data is reloaded The software has automatic data rate detection from 110 to 1200 baud O Programs are debugged with Single Step feature on the key pad O Key pad and dis memory location play subroutines in the ROM monitor are completely accessible 5 KIM 1 is expandable KIM 4 motherboard and KIM 3B memory board allow up to 65K bytes of memory O All required address and data busses and control signals are available options of the KIM 1 connectors O Each 1 0 port is addressed as a normal 6 KIM 1 s instruction set is comprehensive The MOS 6502 architecture has l O register or instructions any memory location can become port Each I O line can be separately programmed with a single status word into the correct memory location 7 KIM 1 s documentation is the best Anywhere 100 page User s Manual O 250 page programming manual O 175 page hardware manual O Pocket reference card O Wall sized schematic e origina All included in the package genuine 9 KIM 1 is value More features power For much less Just 245 00 in quantities of one Quantity prices are available 10 KIM 1 is now almost ready for immediate delivery KIM And soon very soon we ll be able to ship immediately Yes you may have been waiting KIM has been on back order since
121. ock voltages operating at 6 V requiring no adjustments and a higher video output signal The circuitry has been simplified for easier assembly and a two level TTL output is supplied for interfacing In addition a power board is supplied so only a 5 V 1 Amp power source is needed and in the near future Solid State Sales will supply a computer interface card This kit includes all semicon ductors boards data sheets dia grams resistors capacitors and an 8 mm lens Assembly has been simplified so that the only equip ment needed is an oscilloscope soldering iron and some wire The complete kit sells for 349 75 to assemble and test Solid State Sales PO Box 74K Somerville MA 02143 Serial Interface Module The 9650 is an asynchronous serial interface module specifical ly designed for compatibility with the M6800 microprocessor bus It is pin and outline compatible with the Motorola EXORciser and Micromodules and with the MEK6800D2 Evaluation Kit It features full address decoding and fully buffered data address and control lines This module utilizes 8 MC6850 Asynchronous Communications Interface Adapters with full RS 232C sig nal conditioning An on board bit rate generator simultaneously provides 14 standard rates that can be individually strapped to each ACIA The 9650 occupies 16 consecu tive memory addresses The low est 8 of these access the 8 con Some of Sylvanhill s wares PerCo
122. on page 117 Add the following to the lists of available magazines on that page Kilobaud Peter borough NH 03458 The Home Computer Revolu tion is light reading and generally entertaining one of my next reading projects will be Comput er Lib 7 same source which is referred to often in this latest book by Theodor Nelson Gordon Flemming Sylmar CA Home Computers 27 Questions and Answers Vol 1 Hardware 7 95 Vol 2 Software 6 95 Rich Didday dilithium Press Forest Grove OR 1977 These two books fill a definite need Most people who get start ed in the home computer field find themselves in one of three situations They know quite a bit about software but nothing about hardware they know quite a bit about hardware but nothing about software they don t know much about either one The idea behind these books is that you can buy Vol 1 if you re in the first category Vol 2 if you re in the second category or both if you re in the third category That s the idea behind the books but how well do they pull it off Pretty darn well I d say Together the two books repre sent a heavily edited transcript of nine days of conversation be tween two people on the subject of home or hobby computing One of the participants called A because he provides the answers has a strong back ground in computing in general both hardware and software and home computing in par ticular The other participan
123. ontacts the added interface circuitry required and the possibility SELECTRIC TYPEWRITER Fig 2 System block diagram of the computer s hanging up waiting for a missing contact closure because of grease dirt or other problems Open loop software timing by the com puter looked pretty good and as it has turned out it was a trouble free choice In order to do the soft ware timing you have to know accurately the time re quired for each function or allow extra time for the un certainty and thus slow down the output rate The basic timing comes from the rotation of the oper ational shaft which turns at 7 revolutions per second When the cycle clutch is en gaged to type a character it turns at the same speed as the operational shaft The cycle shaft cams are double lobed and so type a character in half a revolution This means that the basic maximum typing speed is 15 characters per second or 67 milli seconds per character which is pretty respectable The pull in time for the solenoids 5 appreciable about ten milliseconds However all of the typewriter functions are initiated by solenoids so this common time doesn t have to be counted as far as the software timing is concerned because the pull in time can overlap the completion of an other function Shift up or shift down must be done as a separate function and not while typing a character A half revolution of the operational shaft is requir
124. ossible head count of 1100 in the aisles That may seem a bit scant in view of the interesting numbers announced by the Chairwhat ever but I like to check little nit picking items like this so every so often I would take a quick run down a few aisles counting the feet and dividing by two There were seven aisles in all with four of them shortened by the cut off corners of the hall This shorten ing just about made up for the space in the three cross aisles My counts confirmed the approx imately 1000 attendance figure during the more crowded times When the crowd density gets to five square feet per person there is no longer room for elbows or much arm movement and shuf fling around is quite difficult and this could account for a total of up to 2200 people in the exhibit aisles With 150 exhibits to see and a total of 1500 minutes of show time maximum no one could spend more than an average of ten minutes per booth and see the whole show The attendance was scant on both Friday and Sunday mornings so very few people managed to get in the entire 1500 minutes The familiarity of the faces by Sunday indicated that a lot of people did come all three days and made an effort to see all of the exhibits Each person who got anywhere near the Kilobaud booth was asked to fill out a questionnaire which would be entered in a drawing for a Caribbean cruise Few passed up the opportunity By Sunday we found that most of th
125. out is rack upon rack of PETs being burned in They burn em in for 48 hours before packing them up for ship ment Normally they have those plastic covers over the burn in racks to make sure that the PETs are hot thus aggravating any troubles that might otherwise turn up later plant where the PET is being pro duced Commodore doesn t want me to spill the beans on how many units they are turning out but I m sure you will be able to get a good idea from my photos They have a big bunch of units going through the production line and then through exhaustive testing The PETs are burned in for 48 hours at a very high temperature in order to bring on any possible failures before ship ment rather than after The small number of sets in for repairs in dicates the quality control system is working very well How long does it take to put together a PET From one end of the production line to the test bench it takes a little over one hour With the large number of PETs coming out of the factory it is amazing that dealers are groan ing over their back orders some were telling us they could sell ten times as many as they are able to get The factory will be increasing its production soon but this still won t take the pressure off By next year 1711 bet they have fac tory several times as large as they have right now few weeks earlier on the ice skating rink in the center of the Tandy building shopping plaza Hy took
126. p 24 one of your cor respondents suggests the formula arc sin X ATN X SQR 1 X 2 This formula has the defect that when X 1 or l a division by zero is required Also when X is close to 1 or 1 ac curacy is impaired through the loss of significant digits in form ing 1 X I suggest instead the formula arc sin X 2 ATN X 1 SOR 1 X X This formula is theoretically exact and preserves the number of significant digits Also X X usually executes faster and more accurately than X 2 The formula arc cos X arc sin X 0 5 n holds in all cases giving the angle between 0 and m radians Charles A McCarthy St Paul MN Meatless Article The quality of articles in Kilo baud has always ranged from fantastic to restating the obvious and have no complaints about this However in the April issue on pages 116 117 I found the biggest waste of paper I have ever seen in your magazine Jim Huff man s Finally 8080 Meets the Fairchild Video Game was a farce It was nothing more than two pages of 9023 a num ber not yet given in any data books will release data in month or so doing some thing should be a piece of cake you could add and you would be able to have the schematic was not avail able at some time in the future will be invaluable Etc am keenly interested in this sub ject and just wanted to express my disappointment H J Kuhman Pit
127. pabilities Aha You know what we re go ing to have then More computer hobbyists 1 wonder what maga zine they ll be buying when they go down to their local computer stores Now what about some of the other beginners reading Kilobaud 1 hope computer stores and readers are directing small businessmen under 5 5 shopping for a system toward Kilobaud We re doing our best to provide material to help them in selecting a system with ar ticles written with them in mind Now we get to the best part all those professional computer en gineers and programmers out there who read Kilobaud You know there really aren t that many people out there who are experts in every single area of this field To put it quite simply there are a lot of software types who are interested in expanding their knowledge in the hardware area and probably even engineers interested in picking up on programming techniques Those people are of course in terested in reading Kilobaud for the same reason as anyone else articles of general interest objec tive hardware and software re views and the ads A good friend of mine recently pointed out something about Byte and Kilobaud that gave me some food for thought He held up a copy of one of the two maga zines and said This magazine is almost exclusively filled with esoteric high level articles and very little in the way of light read ing material
128. ple while you may have purchased ye ECwriter prior to the introductic 1 Every SuperDEC Throughput Optimizer jur state of the art SuperTer n Ye carries a full one year warranty on all now have all of the Super erm s g parts and workmanship But our com ncredible features without having mitment to excellence service goes 94 beyond the warranty Intertec can also hrow out your DECwriter offer on site service contracts for all of your upgraded SuperDEC equipment So when you re ready to pull out ES the guts and screw in the brains contact us at one of the numbers below and we ll give you the name of your local SuperDEC dealer He ll show you what a difference 395 can make Vith the SuperDEC Optimizer installed rou will have such nifty features as bidirec 8 ional printing manual and automatic top orm full horizontal and vertical tabs address X ible and absolute adjustable right and left mar iins an RS 232C interface a double wide character iet and up to 32 user programmable characters You also add an APL character set selective addressing 722 ind an answer back feature at nominal cost your old DEC writer INTERTEC DATA SYSTEMS Eastern Regional Marketing Corporate Headquarters Western Regional Marketing 19530 Club House Road 1851 Interstate 85 South 17952 Sky Park Blvd Gaithersburg Maryland 20760 Charlotte North Carolina
129. r supply is 1 Amp regulated supply got in a kit The 56 V supply was made from a surplus 40 V 1 Amp transformer bridge 1 Amp rectifiers a surplus 1000 uF 100 V filter capac itor but no regulator The interface circuitry was built on Vector 1 inch per forated circuit board and with a Vector wiring pencil and solder through wire All of the circuitry and power supplies were mounted on a plastic cradle in the space under the typewriter mechanism as shown in the photo The third transformer was required because my typewriter motor turned out to be a 208 V motor found a 75 V 1 Amp surplus trans former which connected up to boost the line voltage to 190 V and that was high enough to make the motor start and run properly Timing By Software The Selectric had many contacts on it for use as character input to the com puter and as feedback con tacts for timing purposes had decided not to use the Selectric keyboard for two reasons First felt that the TVT terminal made a more convenient input device and second the type element with the characters that wanted bore no relation to keyboard arrangement My 731 Selectric has non standard keyboard Therefore removed the character input contacts to get them out of the way and make servicinc easier originally thought of using the feedback contacts in a handshaking mode of operation with the computer But then considered the need to maintain c
130. re or a machine language software book since it is really both If the reader could previously build a kit or follow a program he should after digest ing this volume be able to design much of his own hardware and write programs to interface with other devices That sa lot to learn for only ten bucks Ernie Brooner Lakeside MT The Home Computer Revolution Theodor H Nelson The Distributors 702 So Michigan South Bend IN 46618 2 Most computer hobbyists or those about to get into comput ing will find this book easy to read as well as entertaining It is neither a technical book nor a dry history book The author has combined semitechnical material computer historical anecdotes and his forecast of the role of the computer in the future Reading this book I found that my level of interest wavered between near boredom to moder ate interest However because of the nature of the material an other reader might find different peaks and dips of interest For instance as an advocate of the Altair bus I reacted favor ably to the author s repeated sup port of this configuration A reader using the Digital Group bus for example might be disin terested in the Altair bus coverage At the other end of my interest spectrum found the frequent attacks on IBM to be objection able have no particular like or dislike for but I certainly found the repeated negative atti tude distracting It s a mat
131. rested at his business and was held under 100 000 bail A check of Winthrop s finger prints revealed that his true name was Norman Henry Hunt Jr and that he had been a parole violator in California since 1965 Hunt was charged with three counts of false pretense theft as felonies and he entered a guilty plea to the charges Hunt was sen tenced to two years eight months in prison on the Santa Maria charges Although the investiga tion revealed that Hunt had been involved in fraud and false nesses marketing CB radios computer products and jacks for trailers His method of operation has been to move to a town under a new identity rent a house with option to buy and to make con tacts in his field of endeavor recently computer hobbyists Hunt will generally begin his operation by soliciting backing for product design from private parties Often he will sell his qualifications so well that it is the victim s idea to ask Hunt to de sign a product for him Hunt may then start a business and solicit partners He will rent a building hire employees begin a credit line with suppliers After enough equipment has been re ceived from suppliers on credit to look impressive he will apply for a bank loan to start production He will usually go to a local bank rather than a large bank chain If the loan is received Hunt empties the business of its equipment and leaves the area leaving the credi tors and the bank high
132. rning on the typewriter and the power supplies is a little different because the switching circuit can t work with the power supply off To get around this used the CA2 handshake control line to directly operate a relay Radio Shack 275 004 The power relay applies the 115 V ac to the typewriter motor the 5 V and 56 V power supplies The solenoids in the type writer require about 48 V dc at about 100 mA to operate reliably This is too much for the usual TTL device so a driver circuit is required for space Carrier return etc Below these is the relay added to trip the shift mechanism The solenoid near the middle is a keyboard lock out which have not used The typewriter mechanism sits in a plastic cradle which serves as a mounting for the parts for the electrical interface 24 used surplus Motorola MJE340 Darlington tran sistors one for each solenoid All of the solenoids in the typewriter were disconnected from the original circuit and reconnected with common leads to the 56 V supply The transistor collector was connected to the other terminal of the appropriate solenoid with 31N4007 diode to protect the tran sistor from the solenoid fly back voltage A similar fly back protection diode is provided with the power re lay transistors driven directly from the TTL ICs with a series 1k Ohm resistor to limit current The power supply is 56 V to allow for voltage drop in the tr
133. rvice contracts Each terminal comes with a limited 30 day warranty Quanti ties are limited Prices from under 2000 Also available are reconditioned ADM 1s modems and paper tape punch readers COMPUTER TEXTile 10960 Wilshire Blvd Suite 1504 Los Angeles CA 90024 Innotronics Floppy Disk Drives The new Series 400 diskette drive offering an array of new features that were previously un available in the market has recently been introduced by In notronics Unique new features include automatic head unload and stepper motor time outs bidirectional write protect radial stepping ability for truly overlap ping seeks host power failure detector and six different LED activity indicator electronics Both the Model 410 soft sectored IBM compatible and the Model 420 hard sectored provide single and double density recording capability In addition a proprietary data sep arator design coupled with a digital noise filter and a unique way of handling recorded signals results in 35 percent greater data integrity margins The Series 400 also incorpo rates the field tested Innovex mechanical design which in cludes filtered air operating en vironment single side accessibil ity for maintenance mechanical door interlock with a manual override button targeted media loading and a patented wear free diskette hub rated for over 100 000 insertions Prices for the Innovex Series 400 range from 575 in sing
134. s 6502 1802 etc are somewhat limited in capabilities This is the first of several articles discussing methods to expand those capabilities Charles R Carpenter 2228 Montclair Place Carrollton TX 75006 small but useful programs in Tiny BASIC to paraphrase Tom Pittman is a practical reality Getting the most out of your programs is easier if you work with the inter preter s limitations The utility program in Fig 1 shows how to work with some of these lim itations This program is titled Loans but it could be any comparison of WHAT IF alter natives Here s what we ll be working with and without e Decimal numbers not al lowed e Number range limited from 32768 to 32767 TINY BASIC FOR KIM 1 6502 1 BY T PITTMAN PROGRAMMED BY C R CHUCK CARPENTER WSUSJ 2228 MONTCLAIR PL CARROLLTON TX 75006 THESE PROGRAMS ILLUSTRATE BYTE SAVING TECHNIQUES IN LIMITED MEMORY SYSTEMS THE FIRST PROGRAM USED 492 BYTES THE OTHER USED 410 BYTES AN INCREASE OR SAVING OF 82 BYTES IMPLIED STATEMENTS AND ABBREVIATIONS ARE THE REASON PRINT LOANS HOW MANY INPUT N PRINT LET A 0 PRINT INPUT PRINCIPAL IN HUNDREDS PRINT PRINT INPUT P R T X LET I P T R LET O 100 P 1 LET M O X RATE IN PERCENT R TIME IN YEARS T PAYMENTS IN MONTHS 72 characters maximum on Input lines e implied statements and ab breviations to save bytes of memory
135. s If you splash your self wash the affected area im mediately with soap and water e Keep children away from the work site and store the container out of their reach The developing of the photoresist could easily be performed safely in the backyard after sunset The photoresist is not so light sensi tive that night background il lumination would be a problem None of the chemicals used in this process should be stored in a refrigerator that contains food and flammable chemicals should never be stored in any home refrigerator With these precautions and common sense printed circuit boards can safely and successful ly be made at home Jim Warner Board of Studies in Chemistry University of California Santa Cruz CA 95064 The Wired Again I read with interest R W Bur hans letter p 21 regarding the wired OR in the December 1977 Kilobaud and would like to inject some word of warning The wired OR or more correctly wired NOR when used with TTL de vices should be used only I repeat only with open collector types The logic I love Don Lancaster s term or diode logic should be used only repeat only with CMOS devices which have logic levels much more for giving than that of TTL or if the input consists of a switch Anybody who follows Mr Burhans advice and uses diode isolated AND or OR configura tions with normal totem pole output TTL gates of the 7400 or 74LS family is as
136. s Several others present agreed that this was a reasonable change since Phase 1 was redundant signal that could be obtained by inverting Phase 2 which is also present on the bus If no objections are found this change will be considered for ac tion by all manufacturers of the SS 50 bus to make the change of ficial A discussion of possible addi tions or changes to the bus sys tem for MC 6809 processors brought up the subject of moni tor and software compatibility in these machines It was agreed that Mr Dave Shirk of Technical Systems Consultants Inc would be asked to recommend jump table addresses that would be used by all 85 50 manufacturers in these systems This would in sure that all users of this ad vanced processor on the 55 50 bus would be able to interchange hardware and software easily be tween monitors written by dif ferent sources Mr Robert Lentz president of The Micro Works reported that he had conducted some experi ments with high speed processors and that he had found no prob lems with crosstalk or any need for terminations etc at speeds up to 3 0 MHz with a standard SS 50 bus The next meeting of the 55 50 Manufacturers Association will be held at Personal Computing 78 in Philadelphia All manufacturers of SS 50 bus compatible products are invited All users of the bus are also invited to participate in the meeting and to send any sug gestions they may have to any o
137. s are however It s really very simple we re all begin ners to one degree or another The person who just developed an interest in building or using a personal computer and hasn t any background is most definite ly a beginner And speaking of that type of person I recently heard of a company that didn t feel they should be advertising in Kilobaud because of this be ginners magazine image What a hogwash attitude Are they go ing to totally ignore that ever increasing segment of the market Those total novice individ uals need to be examined much more closely because they re coming from several different directions and have different ob jectives in mind Kilobaud and every other magazine in the personal computing field is be ing bought primarily by com puter hobbyists Some of those other magazines purport to be aimed at the mass market those millions of average middle class Americans who will be buy ing home systems in the years to come The key phrase there is will be buying That market hasn t ar rived yet but it will and need less to say we ve all got our eye on it But for right now ap proaching the middle of 1978 Kilobaud is providing a lot of material for this mass market I ve come to this conclusion as the result of recently teaching a couple of one day courses on per sonal computing for the Univer sity of California At the begin ning of both courses
138. s is the case with all computer hobbyists talked about it at 22 work and a friend offered me a surplus IBM 1014 Remote Inquiry Terminal which con tained Selectric Model 731 typewriter So here was my hard copy out put device all that had to do was interface it with my computer Well it s all working now and am very happy with it It makes beautiful copy Now can type assembly listings use my computer as a text editor and type out letters or articles like this one Last January gave a talk about my Selectric Interface at a meeting of the Computer Hobbyist Group of North Texas which was received with a lot of interest Editor John Craig heard about it and suggested an article for Kilo baud So am now sitting at my TVT typing words into RAM and printing them out on the Selectric The Selectric Interface is presented in two parts Part one describes the hardware and part two will cover the software More Than a Printer The 1014 Remote Inquiry Terminal is of early 1960 vintage The Selectric is mounted on a heavy steel desk which is full of power supply relays and diodes didn t have room for the desk so removed the Selectric and discarded the relay en coder and decoder circuitry That meant that had to provide everything between the 6800 output and the sole noids in the Selectric also decided to give my hard copy printer some extra smarts by arranging for comput
139. s to billing form letters pro duced by large computers em ployed by giant corporations The article stated that this soft ware is running on an Imsai 8080 and is being utilized to do battle with one of the largest credit card companies in business Well the results are in and Consumer Computer Inc lost a few battles but won the war The form letters generated by the microprocessor were completely ignored by American Express and its overgrown computer system This was anticipated since any thing short of enclosing your pay ment within a ton of cement is usually insufficient to allow any correspondence to escape from the batch processing syndrome Therefore Consumer Computer Inc was overcome in its first skirmish No billing problem was corrected and a fee for the ser vices of Consumer Computer was certainly not collected from the firm issuing the improper billings Round two saw yours truly taking American Express to New York City s Small Claims Court Running true to form American Express failed to answer the sum mons to appear in court This caused a judgment to be entered against American Express The arbitrator who calculated the amount of the judgment award allowed an added 70 for ex penses largely Consumer Com puter Inc Thus Consumer Computer Inc won an over whelming victory by correcting my billing difficulties and collect ing 70 from Goliath rather than the 25 fe
140. t called Q is an intelligent interested newcomer to the field who has visited the computer stores picked up some literature and bought a few magazines but needs further help to figure out what it all means He doesn t understand too much of what he s read and wants to know for example what is really involved in putting a computer kit together Is he better off getting a fully assembled system Why are there so many different microproces sor chips What does all this RAM ROM PROM EPROM stuff mean What s involved in programming Why are there so many different programming languages What can you really do with a home computer 1024 is 2 which is the number of questions and answers in the two books thus the title for the work But it s more than just a bunch of disjointed questions thrown together The books are well organized and proceed logically from one topic to the next building up your knowledge and tying things together as you read Of course neither book is go ing to enable you to become a professional programmer or hardware designer overnight but they ll give you a better idea of what these people do and intro duce you to some of the basics as they relate to home computing Usually when I read an intro ductory level book or article on computing I find myself saying That s not a very good ex ample or that s sure go ing to mislead somebody These books are a rare except
141. ter of psychology if you like the Altair bus and have something against IBM you ll enjoy the author s comments on the other hand if you don t like the Altair bus structure and have a high regard for IBM you won t enjoy reading this book A little more than half of The Home Computer Revolution is related to the author s predic tions of the future home comput er world Therefore if you are going to read this book do it now very shortly these precari ous prognostications will either be history or wrong guesses Some of the predictions concern ing future home computer input output devices and techniques seem way out but so was 7 984 not very long ago On the positive side 1 thought the historical notes on Mits Cromemco and other companies were very interesting Those read ers new to home computing will find some seldom published background information There are brief hardware de scriptions Altair bus oriented but with home computing mov ing so fast a book would have to be published in loose leaf style to keep up with the hardware changes Only a monthly maga zine such as Kilobaud can hope to keep you informed on the cur rent hardware The program languages de scriptions are short with most languages getting only one para graph The author suggests that a person learn programming with a BASIC interpreter and this is probably what most home com puterists are doing A serious oversight occurs
142. tes This version uses 410 bytes by the prompting question mark and following space This reduces actual data input to 70 characters including the re quired commas between the data entries With the loan amount in hundreds was able to input values for six loans in stead of five To overcome the limited data input situation write programs that will per form calculations hold the results and return for more LOANS HOW MANY 6 data l ve done this on some data processing routines with good results There s another way to ac commodate more data than the line will hold Simply input as many loan numbers or WHAT IFs as needed in line 100 When the program has used the data entered it will ask for more un til the number of N entries is reached in line 320 Question marks will show up each time INPUT PRINCIPAL IN HUNDREDS P RATE IN PERCENT R TIME IN YEARS T PAYMENTS IN MONTHS X 40 10 3 36 40 12 4 48 40 18 5 60 50 10 3 36 50 1 2 4 48 50 18 5 60 LOAN NUMBER 1 INTEREST IS 1200 MONEY OWED IS 5200 PAYMENTS ARE 144 LOAN NUMBER 2 INTEREST IS 1920 MONEY OWED IS 5920 PAYMENTS ARE 123 LOAN NUMBER 3 INTEREST IS 3600 MONEY OWED IS 7600 PAYMENTS ARE 126 LOAN NUMBER 4 INTEREST IS 1500 MONEY OWED IS 6500 PAYMENTS ARE 180 LOAN NUMBER 5 INTEREST IS 2400 MONEY OWED IS 7400 PAYMENTS ARE 154 LOAN NUMBER 6 INTEREST IS 4500 MONEY OWED IS 95
143. that usually communicates only with the CPU If a program has been loaded into memory it will execute starting at location 0000 by returning the DMA switch to RUN and then depressing the RESET switch S6 If the CON TINUOUS SINGLE STEP switch S1 is in CONTINUOUS mode the execution will continue un til a software HALT 76 is en countered or DMA is requested and granted If SINGLE STEP mode is selected each op code must be executed one at a time by toggling the STEPPER DATA LEDS RESET LOAD ADDRESS switch S2 This switch is de bounced and clocks in a logic one to the D flip flop IC2a This in turn allows PRDY to go high via IC4c and 10 PRDY commu nicates with WAIT on the Z 80 MPU As long as WAIT is held low the 2 80 will continue to spin its wheels by executing wait states Activating the STEPPER switch allows the Z 80 to resume normal operation until the next instruction fetch cycle comes up When this happens the Z 80 signals the event by bringing its M1 pin low This signal appears inverted as SM1 on the S 100 bus and will trigger the one shot In turn clears the flip flop once again bringing PRDY low and throw ing the Z 80 back into neutral until the next STEPPER switch toggle One change should be made on the S D Sales CPU card IC20 should be removed from its socket Bend pin 11 outward carefully and replace the IC be careful that pin 11 remains out side th
144. titles such as 11 What is Microcomputer and Introduction to Micro computer Programming They are all informative and readable Unfortunately there are some errors no doubt accidental but possibly confusing to the reader Occasionally the authors give detailed explanation that ends just when you expect some vital truth to be revealed but these rare omissions serve mainly to demonstrate the thoroughness of the rest of the book Each chapter begins with an outline and ends with a summary and some searching questions In light of its format it could well be used as a textbook Let s take chapter 4 to consider the book s style Title Generating an output pulse Outline Objectives definitions 8080 I O instructions device select pulse decoding sample microcomputer program de vice select pulses as control pulses example test and What have you accomplished in this chapter Introduction this chapter you will learn how to generate device select pulses At the end of the chapter the reader is asked to draw a schematic diagram for a circuit that can generate up to 256 dif ferent device select pulses And if you read the chapter you should be able to do the above and a great deal more In following chapters the authors explain the use of these and other signals for the control of outside devices via timing loops and other programming se quences Throughout
145. tores would take the package set it up to work on a system and then call van firms to come in and see it at work It is unlikely that many would pass up the system When you consider that there are over 80 000 such firms around the country you can see that sales could be vigorous There are hundreds of vertical packages that can be developed to help computer stores with their sales and these should bring in handsome royalties Next we come to computer aided instruction and the possibilities for thousands of more programs Every course taught in school and those that should be taught in school are good prospects for this field Home oriented programs will be popular security pro grams general business pro grams games the list is for tunately endless Programs that are usable on more than one system will be checked out on other systems in the Kilobaud labs have most of the microcomputer sys tems set up for this and even our maintenance man is into working up programs Of course we have the TRS 80 16K the PET Altairs Imsai OSI ISC Heath H8 and H11 etc This place is microcomputer heaven Programmers should send in complete listings documen tation some data on how to use the programs and what they can do plus a cassette or disk with the program on it depend ing on the system We would like to get as good a print of the pro gram as possible Programmers intereste
146. tsburgh PA Once in a while I really blow it and this was one of those occa sions It was simply my enthu siasm for the subject and that of many readers that made me de cide to run the article Thanks for the feedback I ll try to be more careful John A Stimulating Response Thank you for sending our book Stimulating Simulations to a reviewer who took the time to read the text and actually put the program listings into the comput er Robert Soltysik s statements Kilobaud April 1978 p 13 al though not in complete agree ment with mine were obviously based on careful examination of the book His objectivity was cer tainly a relief after I read a review of The Devil s Dungeon in the March issue of nterface Age The nterface Age reviewer made statements that indicated he had not entered the program in the computer or even read the sce nario carefully Instead he vent ed his hatred for computer games The Wumpus in particu lar on my poor little book which many readers and publishers have found delightful Thank you for employing intelligent and consci entious reviewers The next time I want to communicate with the West Coast it will be through your magazine There was one problem with the review however My address and the price of the book were omitted Stimulating Simulations sells for 5 and can be purchased from Engel Enterprises PO Box 16612 K Tampa FL 33687 Jane E Engel Publisher
147. ttle computers 3nd TRS 80 Business e Above except includes 32K RAM 14 PRODUCTS Plotters Kit and Assembled Sylvanhills Laboratory Inc has been sold to Pitsco Inc and offers plotter kits and plotters completely assembled The kits require the purchaser to mount them on a drawing surface con sole also available as a new prod uct of Sylvanhills and to do the interconnection between the con trol PC boards and his computer Plotters require an 8 bit parallel I O port and 5 and 24 V power sources A basic 8080 software program is included in the owner s manual Sizes available are 11 x 17 795 in kit form 17 x 22 950 in kit form and 22 x 34 1300 in kit form Consoles priced separately Contact the new offices and manufacturing facilities of Sylvanhills Laboratory Inc PO Box 646 Pittsburg KS 66762 202 Video Camera Kit Solid State Sales 202 Video Camera Kit may be used for visi ble or infrared viewing for char acter recognition with computers with external circuits It will oper ate in a vacuum under water at high altitude or in a magnetic en vironment because there is no high voltage or magnetic deflec tion In addition it may be used for IR surveillance with an IR light source and is excellent for standard surveillance work be cause of its light weight under 1 Ib and small size Some advantages offered in this new kit from previous models are all cl
148. us all over the new Tan dy headquarters building A few blocks away there is an enormous parking lot serviced by a new subway system that ends in the Tandy building This per mits people to park and shop the are over 100 TRS 80s being burned in of the burn in area which goes on and on downtown area and get to the parking lot easily The ground floor ice skating rink is ringed by a shopping plaza Prominent in the plaza were a giant Radio Shack store a Tandy Computer store and a new Tandy Telephone store The elevators go up to the 17th floor from there you have to take an escalator to the top corporate offices While some firms are being run by uptight people who appear to be well on their way to terminal constipation the Radio Shack crowd seems to be having a good time at their work I was sur prised at the large number of hams involved in the higher posi tions most of whom have been reading 73 for years I like that in a person known many of the people either through Radio Shack in Boston or Allied Radio Quite a crew Tandy has built two tower buildings recently both about 19 floors They have a third tower going up soon 45 floors Tandy is dominating downtown Fort Worth Some difference from when I lived in the area about 30 years earlier and the highest point in town was the dung heap at the stockyards After the visit to the offices some talking with various

Kilobaud 1978-06 pages 001-049 Medium

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