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SBC6120 User`s Manual

1. ave gt 7 ZT JUMPERS a ie ALEA EE de RE Adi e QD ds 9 2 8 ode Etro s ete DP e DEED dete De dove boe Qo as 9 HARDWARE DESCRIPTION i nci cn iD Sn ER DRE DIT BR anna Haan 11 3 1 PROCESSOR A ed ce e elo s E E ee ey 11 3 2 MEMORY 12 3 9 CONSOLE TERMINAL an Ebr t 13 34 DISK e eet tec odere ce te ret a coe EE v be eed A e EE ee eed 13 3 5 52 2 ee A eoe er ete e o dede t oe EIER 14 3 6 POST DISPLAY HE a re cte hoe ea 15 SOFTWARE DESCRIPTION coca ted vk edpez sima cie ag 17 4 1 POS mL Eu m 17 4 2 RAM DISK SUPPORT idest 18 4 3 DISK SUPPORT fx ac 18 4 42 205 6 et ee tete leone t beds TE 20 45 LOADING OS 8 ONTO THE 5 6120 21 COMMAND REFERENCE eene sa nasa 44 R4 rn saam nada R4 do dana rada dd duda nsn 25 5 1 SPEGIAL CHARACTERS ooi aeter ab dente bibet sab esee bab tiet 25 52 MEMORY GOMMANDS cote
2. REFERENCE MANUFACTURER PART SUPPLIER STOCK DESCRIPTION DESIGNATOR NUMBER NUMBER 04 Atmel ATF16V8B15PC Arrow CMOS PLD Flash 012 U11 Atmel ATF22V10B15PC Arrow CMOS PLD Flash J4 Comm Con 1184 50G2 Comm Con 50 pin female header U1 CTS Reeves MXO45HS 5000 Digi Key CTX157 5 0000 MHz half size clock oscillator U23 CTS Reeves MXO45HS 4915 Digi Key CTX156 4 9152 MHz half size clock oscillator D2 Dialight 555 4403 Digi Key 350 1371 Quad LED indicator with integral resistors J3 3M 2510 5002 Digi Key MHD10K 10 pin low profile right angle shrouded header J2 3M 2540 5002 Digi Key MHD40K 40 pin low profile right angle shrouded header F1 Littelfuse 473 500 Digi Key F1200CT 0 5A picofuse U9 U10 27C64 Jameco 39845 8K x 8 CMOS EPROM 250ns U16 HD6402 Jameco 43158 CMOS UART U17 Maxim MAX232CPE Jameco 24811 Dual 5V only RS 232 transmitter receiver U18 82C55A Jameco 52425 CMOS Programmable Peripheral Interface 5 2 D1 1N4734 Jameco 178790 6 0V 500mW DO 41 Zener diode 51 C amp K TP11 SH8 ABE Jameco 71642 PC mount right angle push button switch C37 Jameco 94123 47uF 25V radial lead tantalum capacitor C32 C31 C30 C29 Jameco 154860 1uF 25V radial lead tantalum capacitor J1 Molex 15 24 4041 Jameco 117567 4 pin right angle header Jameco 39386 Machined pin DIP sockets 22V10 Jameco 38623 Machined pin DIP socket 16V8 Jameco 40328 Machined pin DIP sockets 27C64 Jameco 41136 Machined pin DIP socket HD 6120 J14 13 12 11 J10
3. Dn Dead cia 26 5 37 3EEGISTERIGOMMANDS 2 A eroe fe Lee 29 5 4 t BREAKPOINT COMMANDS daba 30 5 5 CONTROECOMMANDS ies oberen A eroe 31 5 6 TERMINAL 8 525552646 da 32 b LOAD DUMP GOMMANDSS i estoica ita adria 33 5 8 IDE AND RAM DISK 5 00000 11 33 5 9 MISCELLANEOUS 5 0 0 sd sss sss 36 5 10 ERROR MESSAGE SR eeu a eet 36 ROM FUNCTION cuidada da Cod ERE E RN v 39 6 1 GET ROM VERSION ede oed D ear Seah adire dtes ee 39 6 27 READAWRITE RAM DISK oreet petet and lata deat ues 39 6 3 GET RAM DISK SIZE ca ee ee e tuere doma eae nee em 40 6 4 GET RAM Disk BATTERY 5 5 40 6 55 READ WRITE IDE DISK ie dre e ee e tend 40 6 6 GETADEJDISICSIZE ee e co coded tree 40 6 7 SETIDE Disk PARTITION MAPPING ceeeeeee nono conoce conocen nennen 41 6 8 GET IDE DI
4. SMHO2 2 pin header jumper U3 U2 74HC373 JDR Octal D latch 013 74HC365 JDR Hex tri state buffer U14 74HC245 JDR Octal tri state buffer U15 74HC4040 JDR 12 stage binary ripple counter U19 74HCO5 JDR Hex inverter with open drain outputs 03 09 2003 1 35 PM Page 47 Spare Time Gizmos SBC6120 User s Manual REFERENCE MANUFACTURER PART SUPPLIER STOCK DESCRIPTION DESIGNATOR NUMBER NUMBER U22 U20 74HC74 JDR Dual D flip flop U21 74HC175 JDR Hex D flip flop U24 74HC04 JDR Hex inverter 099 Dallas Semi DS1233D JDR 5V EconoReset U5 Harris HD6120 12 bit microprocessor 08 U7 U6 Hitachi HM6208HP 64K x 4 static RAM Spare Time Gizmos SBC6120 2D PCB Express SBC6120 REV D PC Board C22 C21 C20 C19 C18 C17 C16 C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 0 1uF 50V mono ceramic capacitor 0 1 lead spacing R10 R8 R5 R4 R3 R2 R1 10K 5 1 8W carbon resistor R6 4 7K 596 1 8W carbon resistor Table 17 SBC6120 Parts List REFERENCE MANUFACTURER PART SUPPLIER STOCK DESCRIPTION DESIGNATOR NUMBER NUMBER J1 Comm Con 1185 50G Comm Con 50 pin male female stackable connector Comm Con HW PC600P 1X Comm Con Nylon standoffs Keystone 103 Digi Key 103K ND Coin cell battery holder Z0mm B1 B2 Panasonic CR 2025 Digi Key P188 ND 20mm Lithium coin cell battery U2 U3 U4 U5 628512LP Jameco 157358 512K x 8 low pow
5. Spare lt Time Gizmos SBC6120 USER S MANUAL Second Edition Copyright 2001 2003 by Spare Time Gizmos Visit our web site at www SpareTimeGizmos com Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 1 published by the Free Software Foundation with no invariant sections with the front cover text Portions Copyright 2001 2003 by Spare Time Gizmos and our URL and with no back cover text A copy of this license may be obtained from http www gnu org licenses fdl txt 5 1 3 4 5 6 van OVERVIEW ETSI Em 1 1 1 REGULATORY WARNING nn innert tilii tiii tiet nennen nennen a 2 1 2 SAEETYWARNING31 onde ebur eee cdi see etae o ba cuo exe Cro ro eive Hund 2 1 8 INED BRA 2 D UCEI4 lb 3 2 1 ERRATA He 3 2 25 PART OAOELECTION i5 ni tee dre ob Bun ata ceo Ee en nei 3 2 3 SOCKETS AND a a a ette none 4 24 4 ASSEMBLY ee eoe A a beret Oso enc 6 242 FINAL GHECKOLT sa aa 6 2 6 TOONNECTORS
6. RX01 RXAO 1 KL8E TTY 1001 SYS IDA1 IDA2 IDA3 IDA4 IDA5 IDA6 IDA7 DSK IDO1 IDA1 5 Now click on the WinEight File menu select Open and then type the name SBC6120 IDE into the File Name box Be sure to type the extension DE since that tells WinEight what type of emulated device you want to attach Click the Open button and a dialog will appear that reads 1001 image file D PDP8 SBC6120 SBC6120 IDE will now be created Click OK to proceed or CANCEL to abort Click the OK button and the WinEight status bar should display the messages 03 09 2003 1 35 PM Page 44 Spare Time Gizmos SBC6120 User s Manual Device 001 SBC6120 IDE Disk installed at base address 47 IDO1 Unit O Attached to D PDP8 SBC6120 SBC6120 IDE Finally click the CPU choice in the WinEight menu bar and select Properties In the CPU Properties dialog set the CPU Type to HD6120 check the box that reads Enable BTS6120 Emulation and click the OK button Return to the main OS 8 part of the WinEight window and type BO Instruct BUILD to create a new system disk WRITE ZERO DIRECT Y Answer X to initialize the new system s directory SYS BUILT SAVE SYS BUILD Save this copy of BUILD for later use 6 Congratulations You have now successfully built a bootable OS 8 1001 image Unfortunately it contains only one file the copy of BUILD SV which you just saved there Before it can be useful we need to copy the remaining files
7. scheme into each 4K bank A 512K SRAM chip holds 128 of these 4K banks for a total capacity of 2688 0 PDP 8 pages or 13444 OS 8 blocks A 128K SRAM would contain only 32 banks for a total of 6724 PDP 8 pages 33619 OS 8 blocks Sixty four bytes are wasted in each bank by this packing scheme which works out to about 21 OS 8 blocks lost in each 512K SRAM More clever software could reclaim these but it would require that the three for two packing algorithm split PDP 8 pages across RAM disk banks 4 2 1 VMO1 Handler A standard OS 8 handler known as the VMO1 is available for the SBC6120 RAM disk Since the RAM disk can be mapped into panel memory space only the VMO1 handler uses the HD 6120 PRO instruction to invoke BTS6120 functions that transfer data between RAM disk and main memory see section 6 2 The VMO1 handler implements four units VMAO through corresponding to the four SRAM chips The SRAM chips are completely independent and if one or more are not installed then the corresponding VMO1 units are simply treated as off line and return I O errors when accessed setting a conditional assembly switch the VMO1 handler may be built as a system VMSY or a non system VMNS device The system handler version of the 01 contains a secondary bootstrap which be booted by the BTS6120 BOOT command see section 5 8 3 ATA DisK SUPPORT BTS6120 supports any standard ATA hard disk connected to the SBC6120
8. 1 then you will need to edit out the slash character 2 Create a copy of the OS8V3Q system disk and use FLX8 to copy the IDO1 PA file to it Unfortunately there isn t enough room on the original OS8V3Q diskette so we ll have to delete some files that we won t be using C gt REM BE SURE TO USE COPY B HERE C gt COPY B OS8V3Q RX1 SBC6120 RX1 1 file s copied C gt FLX8 FLX8 gt MOUNT SBC6120 RX1 VIRTUAL RXO1 SFLX8 I mounted virtual diskette on file sbc6120 rx1 FLX8 gt DELETE BASIC BLOAD SV BRTS SV BCOMP SV EABRTS BN SFLX8 I deleted file BASIC AF SFLX8 I deleted file BASIC FF SFLX8 I deleted file BASIC SF FLX8 I deleted file BASIC SV SFLX8 I deleted file BASIC UF SFLX8 I deleted file BLOAD SV SFLX8 I deleted file BRTS SV SFLX8 I deleted file BCOMP SV SFLX8 I deleted file EABRTS BN FLX8 gt DELETE PT8E BN RESEQ BA RKLFMT SV IDS SV SFLX8 I deleted file PT8E BN SFLX8 I deleted file RESEQ BA SFLX8 I deleted file RKLFMT SV FLX8 I deleted file IDS SV FLX8 gt WRITE ASCII IDO1 PA SFLX8 I wrote 01 to IDO1 PA FLX8 gt DIR Directory of SBC6120 RX BUILD SV 33 none 0070 ABSLDR SV 5 1 JUN 93 0131 BITMAP SV 5 none 0136 BOOT SV 5 none 0143 CCL SV 18 none 0150 CREF SV 13 none 0172 DIRECT SV 7 none 0207 you are very brave you can wait and do this step under OS 8 using TECO 03 09 2003 1 35 PM Page 43 Spare Time Gizmos SBC6120 User s Manual
9. EDIT SV EPIC SV FBOOT SV FOTP SV HELP HL HELP SV PAL8 SV PIP RESORC SV RXCOPY SV SV SABR SV TECO SV IDO1 PA ECHO SV SET BATCH SV FUTIL SV SV 10 9 JUN 89 0216 14 none 0230 2 28 MAR 92 0246 8 none 0250 55 none 0260 8 none 0347 19 none 0357 11 none 0402 10 none 0416 6 none 0430 24 none 0436 22 none 0466 33 26 FEB 87 0514 2 none 0653 14 none 0666 10 none 0704 26 15 FEB 87 0716 Total of 360 blocks in 24 files FLX8 gt EXIT FLX8 I dismounting diskette SBC6120 RX1 3 Now run WinEight choose File gt gt Boot from the WinEight menus and browse to the 5 6120 RX01 image you just created Select this file to boot it and you should see the OS 8 prompt appear in the window 4 In the WinEight window type these OS 8 commands PAL IDO1 Assemble the 1001 system handler ERRORS DETECTED 0 LINKS GENERATED 0 RUN SYS BUILD Run the OS 8 configuration utility UN Delete the paper tape handler UN RX8E Delete the RX8E system handler UN RK8E Delete the RK8E system handler SUN RKO5 gt Delete the RK05 non system handler SUN LS8E gt Delete the LS8E line printer handler LO 1001 Load 1001 system handler SIN IDO1 SYS IDA1 7 gt Install the 1001 system handler and IDA1 IDA7 DSK IDO1 IDA1 Set the default work area DSK to IDA1 PR Print the current system configuration
10. KL8E compatible and does not use a HD 6121 there is no particular need to use OS 278 and real OS 8 V3D runs perfectly well Of course you must still avoid using the KT8A extensions in the OS 8 DEVEXT kit as the KT8A IOTs conflict with the 6120 stack instructions up dt _ t POT AAA ott 4 3 1 Figure 1 The SBC6120 03 09 2003 1 35 PM Page 1 1 1 1 2 1 3 Spare Time Gizmos SBC6120 User s Manual REGULATORY WARNING In the United States the Federal Communications Commission requires that devices that use and radiate radio frequency energy be certified in accordance with CFR Title 47 Parts 2 and 15 Other countries will have different requirements The SBC6120 design is not in finished product form and has NOT been approved by the FCC or any other regulatory agency worldwide The user understands that approvals may be required prior to the operation of the SBC6120 and agrees to utilize the SBC6120 in keeping with all laws governing its operation in the country of use SAFETY WARNING The RAMDISK board uses two Lithium coin cell batteries There is a danger of explosion if this type of battery is incorrectly replaced Replace with only the same or equivalent type recommended by the manufacturer Dispose of used batteries only in accordance with the manufacturer s instructions WARRANTY SPARE TIME GIZMOS OFFERS NO WARRANTY EXPRESS OR IMPLIED AS TO THE RE
11. doesn t wait for a carriage return Y continues with the format and anything else including C aborts Format gt RF u gt format RAM disk unit u gt DF pppp gt format IDE disk partition pppp 5 8 4 B Boot The B command boots or at least tries to either RAM or IDE disk It can be used with an argument to specify the device to be booted or without to ask BTS6120 to search for a bootable volume If no valid bootstrap can be found then the message Not bootable is printed NOTE It is currently only possible to bootstrap from unit zero for RAM disk or partition zero in the case of IDE disk Format gt B dd attempt to boot device dd dd may be either VM or ID Example gt Search VMAO then IDAO for a bootstrap gt B IDAO DIR SYS K12MIT SV 33 ABSLDR SV 6 FOTP 5 8 FORLIB RL 265 VMNS BN 1 01 31 output deleted 5 8 5 PM Partition Map The PM command allows the default mapping of OS 8 units to IDE disk partitions to be changed Refer to section 4 3 1 for a detailed description of what disk partitioning is and how is used in 56120 and the 1001 OS 8 device driver PM accepts two arguments both of which are optional The first argument is the OS 8 logical unit number and the second argument a partition number in octal Used without any arguments the PM command will display a list of all eight OS 8 units and their current mappings With one argument PM will display only the mapping for
12. emulator are exact images of what the real SBC6120 and BTS6120 would store in SRAM chip You can simply take a VM1 file and program it byte for byte into a suitable EPROM No preprocessing is necessary 4 5 4 Use the BTS6 120 BU Build The SBC6120 contains 32K twelve bit words of EPROM to store the BTS6120 firmware however BTS6120 actually uses only 8K of this The remaining 24K words can be used to hold two very abbreviated OS 8 system images one for RAM disk and the other for IDE disk The BTS6120 BU command uses these images to build a bootable system on either type device Because of the limited space available only the OS 8 system head can be stored in the SBC6120 EPROM No CUSPS or other programs fit in the EPROM and an OS 8 system built this way will have an empty directory for SYS This is just the absolute minimum amount necessary to have OS 8 boot print a and nothing more probably it s not too useful in the real world Because of copyright concerns the SBC6120 EPROMs supplied by Spare Time Gizmos contain only BTS6120 and DO NOT contain any OS 8 boot images If you want to use this feature on your SBC6120 you ll have to build your own EPROMs To do this you ll first need to build bootable images for both VMO1 and 1001 devices Remember that only the OS 8 system head is preserved by this process so only the OS 8 kernel itself and the device handlers matter Don t waste time loading any CUSPs or other files on to either
13. from the old RX01 OS8 V3Q system diskette to the new 1001 system Remember that the OS8 V3Q diskette is still mounted in WinEight on RX01 unit O it s been mounted there since we booted it back way back in step 3 and we purposefully left the RX01 handler in our new system step 4 so it s easy to copy files from the old system to the new with these commands RUN FOTP Run the File Transfer Program from the old system SYS RXAO BUILD SV V L Copy all files except for BUILD SV ABSLDR SV BITMAP SV BOOT SV CCL SV CREF SV DIRECT SV EDIT SV EPIC SV FBOOT SV FOTP SV HELP HL HELP SV PAL8 SV PIP SV RESORC SV RXCOPY SV SABR SV TECO SV IDO1 PA IDO1 BN ECHO SV SET SV BATCH SV FUTIL SV AC 7 None of the CCL commands e g DIRECTORY COPY etc will work until you issue the command R CCL 03 09 2003 1 35 PM Page 45 Spare Time Gizmos SBC6120 User s Manual 8 Atthis point if you type a DIR command you will see DIR ERROR READING INPUT DIRECTORY Don t panic this happens because the DIR command is attempting to list the directory of DSK not SYS and DSK is the device IDA1 which you have not yet initialized Type this instead DIR SYS BUILD SV 33 FBOOT SV 2 SABR SV 24 ABSLDR SV 5 FOTP SV 8 TECO SV 22 BITMAP SV 5 HELP HL 55 IDO1 33 BOOT SV 5 HELP SV 8 ID01 BN 1 CCL SV 18 PAL8 SV 19 ECHO SV 2 CREF SV 13 PIP SV 11 SET SV 14 DIRECT SV 7 RESORC SV 10 BATCH SV 10 ED
14. image because they will simply be lost The MKSBCROM program is used to combine the BTS6120 firmware with the two disk images The result is two HEX files one for the high order six bits and the other for the low six bits which can be programmed into two 27C256 EPROMSs and then installed on the SBC6120 MKSBCROM high hex low hex bts6120 bin system idl system vml 03 09 2003 1 35 PM Page 23 5 1 Spare Time Gizmos SBC6120 User s Manual COMMAND REFERENCE A large part of BTS6120 is a user interface with an extensive set of commands for poking through memory and registers setting break points uploading and downloading memory and disk images over the console serial port and booting an operating system BTS6120 commands consist of a one or two letter command possibly followed by some arguments In most cases some or all arguments are optional and will have appropriate default values if they are not specified BTS6120 is case insensitive and both commands and arguments may be given in either upper or lower case BTS6120 commands that access memory will accept either full fifteen bit 5 octal digit addresses that include a field or twelve bit 4 octal digit addresses without the field If a twelve bit address is used then the command will always apply a default field value Usually the default field will be the data field from the main memory program s PS register but a few commands that implicitly reference code e g the BP comm
15. of main memory program and then return control to BTS6120 It is the same as the TR command except that no registers are printed Format gt SI execute a single instruction with no register printout Example gt RP 3 SI E 10 single step 3 times and watch location 10 change 00010 2222 00010 2223 00010 2224 5 5 4 TR Trace The TR command will execute one instruction of the main memory program and then print the registers It always executes one instruction but it may be combined with the RP command to execute multiple instructions Format gt TR execute a single instruction then print the instruction and registers 03 09 2003 1 35 PM Page 31 5 6 Spare Time Gizmos SBC6120 User s Manual Example gt RP 10 TR execute 10 instructions and watch the registers IR gt 1123 gt 1212 PS gt 5000 AC gt 0200 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 6034 PC gt 1213 PS gt 4000 AC gt 0215 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 3034 PC gt 1214 PS gt 4000 AC gt 0000 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 6032 PC gt 1215 PS gt 4000 AC gt 0000 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 4322 PC gt 1323 PS gt 4000 AC gt 0000 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 1722 PC gt 1324 PS gt 4000 AC gt 7553 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 2322 PC gt 1325 PS gt 4000 AC gt 7553 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 7450 gt 1327 PS gt 4000 AC gt 7553 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 1034 P
16. solder your only 6120 chip to the board 03 09 2003 1 35 PM Page 5 2 4 2 5 Spare Time Gizmos SBC6120 User s Manual ASSEMBLY HINTS Don t install any ICs until you ve read the next section and when you do install the ICs notice that they are all oriented with pin one to the top or right except 1072 011 22V10 This one had to be oriented backwards to improve the trace routing Many people have had difficulty getting the correct EPROM into the correct socket It does no harm to reverse them but it won t work either Remember that the PDP 8 numbers its bits backward from the usual convention so the EPROM containing bits DX0 5 is the HIGH EPROM and bits DX6 11 are the LOW EPROM In the silk screen see Appendix C U9 the one closest to the RESET push button is the HIGH EPROM and U10 is the LOW Seven 10K ohm resistors and one 4 7K resistor are used in the SBC6120 the lone 4 7K resistor is the one located between the UART and the 1072 GAL Don t waste your time looking for R7 and R9 they do not exist in this revision of the SBC6120 Twenty two 0 1uF 50VDC monolithic bypass capacitors are used the SBC6120 These are not identified in the silk screen however their positions are shown in red in Appendix C Capacitors C29 C30 C31 and C32 1 25V tantalum are polarized devices and must be installed correctly The polarization is not shown on the silk screen however if you hold the SBC6120 PC board so t
17. 000 gt BR remove all breakpoints regardless of address gt BL None set 5 4 4 P Proceed The P command is used to proceed after the main memory program has stopped at a breakpoint You can t simply continue at this point because the PC points to the location of the breakpoint 03 09 2003 1 35 PM Page 30 5 5 Spare Time Gizmos SBC6120 User s Manual and the Continue command would simply break again instantly The P Proceed command gets around this problem by first executing a single instruction and then continuing normally Format gt P proceed past a breakpoint CONTROL COMMANDS 5 5 1 ST Start The start command initializes the CPU registers and all I O devices and then transfers control to a main memory program A single optional argument may be given to specify the start address of the main memory program If the start address is omitted then the default is location 7777 of field O this is a little strange by PDP 8 standards but its the typical reset vector for 6100 and 6120 devices Formats gt ST gt start the program at location 77777 gt ST aaaaa Start the program at location aaaaa 5 5 2 C Continue The command will restore all saved main memory registers and resume execution of the main memory program at the location indicated by the PC Format gt restore the main memory registers and continue 5 5 3 51 Single Instruction The 51 command will execute a single instruction
18. 09 2003 1 35 PM Page 38 6 1 6 2 Spare Time Gizmos SBC6120 User s Manual ROM FUNCTION CALLS The HD 6120 has four special instructions PRO through PR3 which when executed from a main memory program cause a trap to panel memory PR3 is used as a break point trap by BTS6120 and this instruction should not be used in programs PR1 and PR2 are unused and will cause an BTS6120 to print the message Unknown trap at if one is executed BTS6120 uses PRO as a general purpose way for main memory programs to invoke special functions within the BTS6120 ROM firmware The convention is that PRO is immediately followed by a function code and then zero or more arguments depending on the specific function Trap Operation PRO 6206 Call SBC6120 ROM function 1 6216 Unused PR2 6226 Unused PR3 6236 Break point trap Table 15 Panel Trap Instructions GET ROM VERSION PRO function 0 returns the version of the BTS6120 ROM firmware PRO call the SBC6120 ROM firmware 0 function code for Get Version return with ROM version number in the AC The BTS6120 version is treated as a single octal number and as of this writing the latest version is 2038 READ WRITE RAM Disk PRO function 1 is used to read or write the SBC6120 RAM disk PRO call the SBC6120 ROM firmware 1 function code for RAM disk I O lt argl gt R W bit page count buffer field and unit lt arg2 gt buffer address
19. 471 Read PPI port B PRPC 6472 Read PPI port PWPA 6474 Write PPI port A and clear the AC PWPB 6475 Write PPI port B and clear the AC PWPC 6476 Write PPI port and clear the PWCR 6477 Write PPI Control Register and clear the 21 G1 and G2 refer to the IOT GROUP 1 Land IOT GROUP 2 L signals exchanged between the IOT1 GAL and the IOT2 GAL 22 This table shows the logical state of the CO L C1 L SKIP Land BYTE READ L signals however remember that these are active low Thus signal which is TRUE asserted in this table will be low 23 This refers to the signal BYTE READ L which forces the four most significant DX bits to zero during an 1 O read from an 8 bit device The KL8E IOTs 6030 KCC 6035 KIE 6040 SPF and 6045 SPI are not implemented by the SBC6120 The IOTs 6033 6037 6043 and 6047 are not implemented by either the SBC6120 or the KL8E All these IOTs function as no ops KEYBOARD FLAG H 26 PRINTER FLAG 03 09 2003 1 35 PM Page 51 Spare Time Gizmos SBC6120 User s Manual IOT Gt G2 co c1 SKIP BYTE DESCRIPTION SYSTEM MMO 6400 Select ROM RAM memory map section 3 2 MM1 6401 Select RAM ROM memory map MM2 6402 Select RAM only memory map MM3 6403 Select RAM RAM disk memory map 6410 Load RAM disk address register and clear t
20. 57 1777 output deleted 71770 7170 1717 7172 1737 7147 7715 7671 7177 72000 0200 2010 0202 2030 0240 0025 0602 0207 03 09 2003 1 35 PM Page 26 Spare Time Gizmos SBC6120 User s Manual 5 2 2 EP Examine Panel Memory The EP command is identical to E except that panel memory is examined rather than main memory 5 2 3 D Deposit Main Memory The D command allows the user to deposit one or more words in memory The first argument specifies the memory address to be modified and the second argument is the value to be stored Any number of values may be deposited into consecutive locations if they are separated by commas Formats gt D aaaa bbbb gt deposit bbbb in location aaaa of the current data field D faaaa bbbb deposit bbbb in location aaaa field gt D faaaa bbbb cccc dddd deposit numbers bbbb cccc dddd etc in consecutive memory locations starting at faaaa Examples D 0123 4567 E 0123 60123 4567 D 40000 1 2 3 4 gt E 40000 40007 40000 0001 0002 0003 0004 7704 0705 4371 6607 5 2 4 DP Deposit P anel Memory The DP command is identical to D except that panel memory is changed rather than main memory WARNING There is no protection against corrupting BTS6120 when using this command 5 2 5 BM Block Move Memory The BM command is used to move blocks of memory words from one location to another It has three parameters the source address range two 15 bit numbers and the desti
21. 6 6 DD9 1 7 DD5 PB5 8 DD10 PA2 9 DD4 10 DD11 PA3 11 DD3 PB3 12 DD12 4 13 DD2 PB2 14 DD13 PA5 15 DD1 PB1 16 DD14 PA6 17 DDO 18 DD15 7 19 GND 20 N C 21 N C 22 GND 23 DIOW L 24 GND 25 DIOR L PC3 26 GND 27 N C 28 N C 29 30 GND 31 N C 32 N C 33 DA1 1 34 N C 35 DAO 36 DA2 PC2 37 CS1FX L PC6 38 CS3FX L PC7 03 09 2003 1 35 PM Page 7 Spare Time Gizmos SBC6120 User s Manual Pin Signal PPI Pin Signal PPI 39 DASP 40 GND Table 1 Connector J2 2 6 3 Console J3 is a ten pin header which connects to the console terminal and is intended to be used with a standard PC DB9 or DB25 if you prefer cable Note that only TXD RXD and ground are connected Pin Signal 5 TXD 3 RXD 9 GND Table 2 Connector J3 J3 has exactly the same pin out as a PC and therefore if you intended to connect the SBC6120 to a PC s COM port you will want to use a null modem serial cable with female DB9 DB25 connectors on both ends 2 6 4 Expansion J4 is a general purpose expansion connector which can be used for the RAM disk daughter board or other I O expansion options If you design your own expansion board to fit this connector then use care to minimize loading since these signals are not buffered on the SBC6120 In particular it would probably not be a good idea t
22. C gt 1330 PS gt 4000 AC gt 7770 gt 0000 SP1 gt 0000 SP2 gt 0000 IR gt 7650 PC gt 1332 PS gt 4000 AC gt 0000 gt 0000 SP1 gt 0000 SP2 gt 0000 5 5 5 EX Execute IOT The EX command allows a user to type in and execute an IOT instruction directly from the terminal which can be very useful for testing peripheral devices The first argument is the octal code of the IOT to be executed and the second which is optional is a value to be placed in the AC before the IOT is executed If it is omitted zero is placed in the AC After the instruction is executed the word SKIP is typed if the instruction skipped along with the new contents of the AC WARNING Some care must be exercised with this command since executing the wrong IOT can crash BTS6120 Formats 6xxx execute IOT 6xxx instruction and print the results gt EX 6xxx yyyy gt put yyyy in the AC and then execute IOT 6xxx Examples 6471 execute IOT 6741 gt 0002 gt EX 6474 1176 put 1176 in the AC and execute IOT 6474 Skip gt 0000 5 5 6 MR Master Reset The MR command executes CAF instruction which asserts IOCLR L and initializes all external I O devices It then it resets the saved state of the main memory program to the default values re initializes the IDE disk and finally resets the disk partition map From the point of view of an device or a main memory program this is equivalent to pressing the RESET button This command does not
23. Display IOTs 12 These signals are inverted in the hardware so that writing a 1 bit to the register asserts the signal 13 The POST bits are numbered according to the PDP 8 tradition so for example IOT 6444 would light LED PO 03 09 2003 1 35 PM Page 15 4 1 Spare Time Gizmos SBC6120 User s Manual SOFTWARE DESCRIPTION The 8KW EPROM contains the BTS6120 firmware which has these features gt A power on self test POST of the SBC6120 hardware including the CPU a memory test for EPROM RAM and RAM disk and a test of all peripheral devices gt Commands to examine and change main memory or panel memory plus commands to clear memory move memory blocks compute checksums perform word searches etc Commands to examine and modify all 6120 registers The ability to set break points in main memory programs and to execute single instructions and generate instruction traces A BIN format loader for loading paper tape images through the console port RAM disk I O functions to assist the OS 8 VMO1 handler IDE disk I O functions to assist the OS 8 1001 handler Commands to upload and download both RAM and IDE disk over the serial port An OS 8 bootstrap for both RAM and IDE disk ON WV Figure 6 SBC6120 Software Architecture POST If some part of the SBC6120 isn t working say for example the RAM BTS6120 would like to provide some diagnostic information before it ends up
24. IDE disk and load them with files from the PC You can now disconnect the IDE disk from your PC and reconnect it to the SBC6120 If you changed the disk to a slave drive be sure to change it back to a master before reconnecting it since BTS6120 will not recognize a slave drive If all is well you should be able to power up the SBC6120 and use the B ID command to boot OS 8 from the IDE disk 4 5 2 Download a bootable OS 8 image over the serial port It is also possible to take an 1001 or VMO1 image file on the PC convert it to ASCII text and then download that text to the SBC6120 over the console serial port The BTS6120 firmware contains two commands RL and DL for just this purpose The disadvantage to this scheme naturally is that it is slow An image of a 512kb RAM disk requires approximately 2199k bytes in ASCII and takes about forty five minutes to download an IDE disk partition would take about three hours The MKDLTXT program will convert either a VMO1 1001 disk image to ASCII text in a format suitable for BTS6120 For example MKDLTXT system vml gt system txt will convert the file VMO1 image system vm1 to ASCII text and write the result to standard output which is redirected to the file system txt The same command is used to convert an IDO1 image to text MKDLTXT automatically determines the input type by the file extension The converted text files include a checksum for each disk block which BTS6120 uses to guard again
25. IDE interface Nearly all hard disks with IDE interfaces are ATA conversely nearly all non hard disk devices with IDE interfaces are actually ATAPI and not ATA ATAPI requires a completely different protocol which BTS6120 does not support and BTS6120 will simply ignore any ATAPI devices connected to the IDE interface BTS6120 supports only a single physical drive which must be set up as the IDE master and any IDE slave device will be ignored Since BTS6120 does not support cylinder head sector C H S addressing the hard disk used must support logical block addressing LBA instead All modern IDE ATA drives support LBA as do most drives manufactured in the last five or six years however some very old drives may not If BTS6120 detects ATA drive that does not support LBA it will display the message IDE Not supported during startup and there after ignore the drive 14 CD ROMs ZIP drives LS120 drives etc 03 09 2003 1 35 PM Page 18 Spare Time Gizmos SBC6120 User s Manual All IDE devices regardless of vintage transfer data in sixteen bit words and each sector on an ATA disk contains 512 bytes or 256 sixteen bit words When writing to the disk BTS6120 converts twelve bit PDP 8 words to sixteen bits by adding four extra zero bits to the left and when reading from the disk BTS6120 converts sixteen bit words to twelve bits by simply discarding the most significant four bits No packing is done This conveniently means th
26. IT SV 10 RXCOPY SV 6 FUTIL SV 26 EPIC SV 14 25 FILES IN 361 BLOCKS 3678 FREE BLOCKS 9 Before we can attempt to initialize DSK we have to deal with another problem OS 8 PIP doesn t recognize the 01 or IDO1 devices and so we cannot use the ZERO command to initialize an empty file system on IDA1 Fortunately this is a common problem and it was well documented by DEC how to patch PIP to add additional devices That s what we ll do next GET SYS PIP ODT 13643 5300 J gt Set the default size VMOT devices 13644 1 J Set the size for 1001 devices 13645 c SAVE SYS PIP 10 Now we re ready to initialize the DSK device First we have to attach another IDO1 image file to the IDA1 device by clicking File on the WinEight menu bar and selecting Open Enter another file name e g DSK IDE and you should go thru the same sequence that you first saw in step 5 except that this time you will see 1001 Unit 1 Attached to D PDP8 SBC6120 DSK IDE Return to OS 8 and type ZERO IDAO DIR IDAO 0 FILES IN 0 BLOCKS 4088 FREE BLOCKS Pay particular attention to the number of free blocks 4088 1337 for a VM01 then you have made a mistake patching PIP Congratulations You now have a bootable system ready to transfer to your SBC6120 03 09 2003 1 35 PM Page 46 Spare Time Gizmos B PARTS LIST SBC6120 User s Manual
27. LIABILITY OR ACCURACY OF THE SBC6120 DESIGN SPARE TIME GIZMOS OFFERS NO WARRANTY EXPRESS OR IMPLIED AS TO THE ACCURACY OF THE INFORMATION PRESENTED IN THIS DOCUMENT SPARE TIME GIZMOS OFFERS NO WARRANTY EXPRESS OR IMPLIED AS TO THE SUITABILITY OR CORRECTNESS OF ANY SOFTWARE OR FIRMWARE SUPPLIED IN CONJUNCTION WITH THE SBC6120 SPARE TIME GIZMOS MAKES NO REPRESENTATIONS AS TO THE SUITABILITY OF THE SBC6120 FOR ANY APPLICATION IT IS SOLELY AND EXCLUSIVELY YOUR RESPONSIBILITY TO EVALUATE THE ACCURACY COMPLETENESS AND USEFULNESS OF THE SBC6120 AND ALL RELATED DESIGNS SOFTWARE AND OTHER INFORMATION PROVIDED BY SPARE TIME GIZMOS THE ENTIRE RISK AS TO THE USE AND PERFORMANCE OF THE SBC6120 IS ASSUMED SOLELY BY YOU NO REPRESENTATION OR OTHER AFFIRMATION OF FACT INCLUDING BUT NOT LIMITED TO STATEMENTS REGARDING CAPACITY PERFORMANCE OF PRODUCTS OR SUITABILITY FOR USE WHETHER MADE BY SPARE TIME GIZMOS EMPLOYEES OR OTHERWISE WILL BE DEEMED TO BE A WARRANTY FOR ANY PURPOSE OR GIVE RISE TO ANY LIABILITY ON THE PART OF SPARE TIME GIZMOS THE WARRANTIES AND CORRESPONDING REMEDIES AS STATED IN THIS SECTION ARE EXCLUSIVE AND IN LIEU OF ALL OTHERS WRITTEN OR ORAL SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES SO THE ABOVE EXCLUSION MAY NOT APPLY TO YOU THE LIMITED WARRANTIES AND CONDITION REFERENCED ABOVE GIVE YOU SPECIFIC LEGAL RIGHTS YOU MAY HAVE OTHERS WHICH VARY FROM JURISDICTION TO JURISDICTION IN NO EVENT SHALL SPA
28. PC you can take your SBC6120 s IDE disk and physically connect it to the PC and then use the MKIDO1 program to transfer the image file to the disk Most likely you will want to connect your SBC6120 s IDE disk to the PC as a slave drive since you ll still want another master IDE disk containing Windows or at least DOS for booting the PC It s conceivable that the SBC6120 s disk could be the only IDE disk on the PC and the PC booted from either a floppy or a SCSI disk but that s left as an exercise for the reader After you ve temporarily connected the SBC6120 s IDE disk to a PC you can use the MKIDO1 program to write an IDO1 disk image from the PDP 8 emulator to the physical drive For example MKIDO1 ul w0 os8 idl The ul option tells MKIDO1 to use IDE unit 1 the primary slave as the target drive wO instructs it to write SBC6120 partition 0 and os8 id1 is the name of the IDO1 image file from the emulator The PDP 8 emulator must write the image file in exactly the same format that the SBC6120 uses WinEight does as MKIDO1 simply copies the entire file verbatim to the IDE disk The Spare Time Gizmos FLX8 program is also able access a physical IDE disk in the SBC6120 OS 8 format and it knows how to transfer files between DOS and 5 8 file systems If you have other files you want to copy to your SBC6120 source files games whatever now is a convenient time to use FLX8 to initialize one or more other partitions on the SBC6120 s
29. RE TIME GIZMOS OR ITS EMPLOYEES BE LIABLE FOR ANY COSTS OR DIRECT INDIRECT PUNITIVE INCIDENTAL SPECIAL CONSEQUENTIAL DAMAGES OR ANY OTHER DAMAGES WHATSOEVER INCLUDING WITHOUT LIMITATION DAMAGES FOR COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOST PROFITS LOSS OF DATA INTERRUPTION OF BUSINESS OR LOSS OF USE ARISING OUT OF OR IN ANY WAY CONNECTED WITH THE USE OR PERFORMANCE OF THE SBC6120 YOUR RELIANCE ON THE SBC6120 OR RESULTS FROM MISTAKES OMISSIONS INTERRUPTIONS DELETION OF FILES ERRORS DEFECTS DELAYS IN OPERATION OR TRANSMISSION OR ANY FAILURE OF PERFORMANCE WHETHER BASED ON CONTRACT TORT STRICT LIABILITY OR OTHERWISE EVEN IF SPARE TIME GIZMOS HAS BEEN ADVISED OF THE POSSIBILITY OF DAMAGES BECAUSE SOME STATES JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES THE ABOVE LIMITATION MAY NOT APPLY TO YOU IN NO EVENT SHALL SPARE TIME GIZMOS LIABILITY IN THE AGGREGATE EXCEED THE SUMS ACTUALLY PAID BY YOU TO SPARE TIME GIZMOS AND ACCEPTED BY SPARE TIME GIZMOS FOR THE USE OF THE SBC6120 03 09 2003 1 35 PM Page 2 2 1 2 2 Spare Time Gizmos SBC6120 User s Manual ASSEMBLY Many thanks to Steve Loboyko Paul Schmidt John Wren Jim Kearney and the other SBC6120 builders who contributed their experiences and suggestions to this chapter ERRATA There are no known errors in Revision D ofthe SBC6120 board PART SELECTION The complete parts list fo
30. S6120 Panel trap at fpppp An unused panel trap instruction either PR1 or PR2 was executed by the main memory program atlocation pppp None set No breakpoints are set for the BL command Not set No breakpoint is set at the address given in the BR command Already set A breakpoint is already set at the address given in the BP command Table full The breakpoint table is full A maximum of eight breakpoints can be set at one time Wrong order The arguments given to the command are in the wrong order e g E 7000 4000 Wrap around A BM command attempted to increment past address 77777 I O Error An error occurred during RD DD RL or DL command This be caused by an invalid page block number or it could indicate a hardware problem 03 09 2003 1 35 PM Page 37 Spare Time Gizmos SBC6120 User s Manual Checksum error checksum of the data downloaded in a RL or DL command doesn t match No bootstrap The B command could not find a secondary bootstrap see section 4 4 IDE Not supported The attached IDE disk cannot be supported by BTS6120 see section 4 3 IDE Not detected No ATA disk was found on the IDE interface RAM Battery FAIL Both backup batteries for the RAM disk have failed and the RAM disk contents may be corrupted Illegal PRO function at fpppp The main memory program has executed a PRO instruction with an invalid function code see section 6 03
31. SK PARTITION MAPPING krtien nr nest 41 6 95 CGOPYMEMORY kw ecu 41 BUILDING OS 8 FOR THE SBC6120 1 1 1 4 2 1 ra anne 43 PARTS LIS Tiida 47 SIEIESCREEN 5 49 555 51 Spare Time Gizmos SBC6120 User s Manual OVERVIEW The SBC6120 is a conventional single board computer with the typical complement of RAM EPROM and interfaces What makes it unique is that the CPU is the Harris HD 6120 PDP 8 on achip Yes a real PDP 8 The 6120 is the second generation of single chip PDP 8 compatible microprocessors and was used in Digital s DECmate l III and 111 personal computers The SBC6120 can run all standard DEC paper tape software such as FOCAL 69 with no changes what so ever Simply use the ROM firmware on the SBC6120 to download FOCAL69 BIN from a PC connected to the console port or use a real ASR 33 and read the real FOCAL 69 paper tape if you re so inclined start at 00200 and you re running OS 278 OS 78 and yes OS 8 V3D or V3S can all booted and run on the SBC6120 using either RAM disk or IDE disk as mass storage devices Since the console interface in the SBC6120 is
32. and will use the instruction field instead Generally this is useful however occasionally it can lead to unexpected results and it s always safest to give full five digit address SPECIAL CHARACTERS 5 1 1 Command Editing Control Characters While entering commands BTS6120 recognizes several control characters for command editing CHARACTER FUNCTION Control H Delete the last character entered Backspace echoes as backspace space backspace RUBOUT Delete the last character entered Delete echoes the character deleted Control R Retype the current command line including all corrections Control U Cancel the current command line and start another Control M Ends entry of the current command and starts interpreting it Return Table 13 Command Editing Control Characters 5 1 2 Output Control Characters BTS6120 recognizes three special characters to control terminal output CHARACTER FUNCTION Control S XOFF Suspend output until an XON is received Control Q XON Resume output after an XOFF Control O Suppress output acts as a toggle Table 14 Output Control Characters 5 1 3 Control C The Control C character may be used at any time to interrupt the current command and return to the BTS6120 prompt For example E 1234 and E 01234 don t necessary refer to the same location 03 09 2003 1 35 PM Page 25 5 2 Spare Time Gizmos SBC6120 Use
33. ar transmit flag but not the AC TPC 6044 Load AC into transmit buffer but don t clear flag TLS 6046 Load AC into transmit buffer and clear the flag Table 6 Console Terminal IOTs The console interface in the SBC6120 does not use a 6121 so be none of the skip on flag and clear it nonsense with KSF or TSF that plagued the DECmate family If a daughter board is to be installed which will replace the standard PDP 8 console e g a VT52 video terminal emulator then SBC6120 onboard serial port must be disabled to prevent any conflicts The SBC6120 implements two special IOTs which allow the device codes used by the onboard serial port to be changed IOT Function SSLUCM 6412 Select SLU console mode device codes 03 04 SSLUSM 6413 Select SLU secondary mode device codes 36 37 Table 7 Onboard Serial Port Mode 10715 Executing the SSLUSM IOT would cause the SBC6120 onboard serial port to respond to device codes 36 37 e g KSF would become 6361 TLS would be 6476 etc which allows an external device on the expansion bus to respond to the standard console 03 04 IOTs Executing the SSLUCM would return the onboard serial port to its normal console 03 04 assignment A normal program would ordinarily never worry about this BTS6120 automatically detects at startup whether a secondary console device is present and configures the SBC6120 onbo
34. ard serial port accordingly The SSLUCM and SSLUSM IOTs were first implemented in revision 2 of the IOT2 PLD The original version of the SBC6120 did not have these instructions the onboard SLU device codes were fixed at 03 04 The software can easily determine which version of the PLD is installed by setting the AC to a non zero value and then executing either SSLUCM or SSLUSM On the original SBC6120 both these IOTs are NOPs which will leave the AC unchanged however with the revision 2 PLD the AC will be cleared RAM Disk A daughter board is available which plugs into the SBC6120 expansion header and contains a DS1221 SRAM controller one or two Lithium backup batteries and sockets for up to four byte wide low power CMOS SRAM chips Each socket can contain a 512kb SRAM a 128kb SRAM 1 Or SPI depending on which manual you read 03 09 2003 1 35 PM Page 13 3 5 Spare Time Gizmos SBC6120 User s Manual or nothing The maximum capacity ofthe RAM disk array is thus 2Mb a respectably sized disk for OS 8 M ters ee ee ee ee ee ee e lt PI ps e DIR SL IF TET EIER DREIER STEIN AAA Figure 4 RAM disk daughter board The SBC6120 maps these RAM chips into panel memory via the memory decode GAL and when memory map 3 see 3 2 is enabled all indirect references to panel memory will access the RAM disk array Since the RAM disk is only a byte wide write operations
35. at each ATA sector holds 256 PDP 8 words or exactly one OS 8 block It also means that one quarter of the disk space is wasted in this era of multi gigabyte disks that hardly seems like an issue 4 3 1 Partitioning OS 8 handlers and the OS 8 file system use a single twelve bit word to hold block numbers which means that OS 8 mass storage devices are limited to a maximum of 4096 blocks Using the BTS6120 non packing scheme for storing data 4096 PDP 8 blocks are exactly 2Mb Clearly if a single OS 8 device corresponds to an entire hard disk then nearly all of the disk space would be wasted The normal solution is to partition the hard disk into many OS 8 units with each unit representing only a part of the entire disk Since OS 8 cannot support a single unit larger than 2Mb there isn t any point in allowing partitions to be larger than that and since the smallest drives available today can hold hundreds if not thousands of 2Mb partitions there isn t much point in allowing a partition to be smaller than that either Because of this BTS6120 supports only fixed size partitions of 2Mb each This greatly simplifies the software since a twenty four bit disk sector number can now be calculated simply by concatenating a twelve bit partition number with the twelve bit OS 8 relative block number RBN No super block with a partition table is needed to keep track of the sizes and positions of each partition and the OS 8 handler is simplified since ea
36. bb until interrupted by a Control C 5 9 3 VE Version The VE command types the name version number checksum and copyright notice for BTS6120 Example SBC6120 ROM Monitor V173 Checksum 0164 1744 14 FEB 01 21 18 54 Copyright C 1983 2001 Spare Time Gizmos All rights reserved ERROR MESSAGES BTS6120 cannot understand the command This is usually a syntax error of some kind 03 09 2003 1 35 PM Page 36 Spare Time Gizmos SBC6120 User s Manual Breakpoint at The main memory program has stopped at a breakpoint Since BTS6120 uses PR3 as a breakpoint trap this same message will occur if you inadvertently use this instruction in your program Memory error at fpppp BTS6120 commands that modify memory e g D FM BM LP etc read back each memory location after it is written to verify that the hardware works correctly This message indicates that the memory at location pppp failed this verification Illegal value The argument to a command e g TP TW EX etc is outside the legal range Search fails The ws command failed to find any matching words Halted at fpppp The main memory program has executed a HLT 7402 instruction at location pppp Unknown trap at fpppp Control panel mode has been entered and BTS6120 is unable to determine the reason Break at fpppp The BREAK key has been pressed on the console terminal which forces entry to BT
37. bootstrap is overwritten by this data and the CPU just ends up there The secondary bootstrap is defined in the header of the system device handler and OS 8 BUILD copies this code from the handler to block zero when it builds the system device The second half of block zero contains the system handler that is what s resident in page 7600 while OS 8 is running plus some device independent OS 8 resident code that BUILD wraps around it All of the second half of block zero must be loaded into page 7600 field O by the secondary bootstrap The remainder of the first half of block zero the part after the secondary bootstrap contains the OS 8 resident code for field 1 This starts at offset 473 and needs to be loaded into the corresponding locations of page 7600 field 1 The remaining words in page 7600 field 1 i e those that occupy the same space as the secondary bootstrap are used by OS 8 for tables and their initial values are unimportant Most devices simply copy the entire first half of block zero to page 7600 field 1 e All this discussion presupposes a single page system handler as we have for both the VMO1 and 1001 For a two page system handler BUILD will put the second handler page in the first half of block 66 and the secondary bootstrap is also responsible for moving it from here into memory page 7600 field 2 e everything has been loaded the secondary bootstrap can simply jump to location 7600 field 0 to loa
38. ch as Bob Supnik s could undoubtedly be used if someone is willing to write the necessary code for 1001 and VMO1 emulation The general plan is to use the emulator to boot OS 8 from standard media e g RX01 RKO5 8001 etc load and compile the SBC6120 1001 and VMO1 device drivers and then use the OS 8 BUILD program to build a bootable IDE or RAM disk image file If you have no idea how to go about using BUILD to configure an OS 8 system then you should read Appendix A for a brief summary of the procedure Once you have a bootable 1001 or VMO1 image you can use the emulator to transfer whatever OS 8 CUSPS you like from your OS 8 system to the SBC6120 boot image After that the only tricky part is to transfer the RAM disk or IDE disk image from your PC to the SBC6120 NOTE The copyright for OS 8 is still held by Digital Equipment Corporation and Spare Time Gizmos cannot supply OS 8 software for your SBC6120 DEC has kindly granted permission to use OS 8 on Bob Supnik s PDP 8 emulator however the legal status of using OS 8 on home built hardware is uncertain 7 subsequently Compaq Computer and subsequently to that Hewlett Packard 03 09 2003 1 35 PM Page 21 Spare Time Gizmos SBC6120 User s Manual That said it isn t hard to find copies of OS 8 on the Internet and a little surfing should lead you to what you need 4 5 1 Building a bootable IDE disk on the PC Once you ve built a bootable OS 8 IDO1 disk image file on your
39. ch disk partition is always the same size A twenty four bit sector address permits disks of up to 8 GB to be fully used which seems more than enough for a PDP 8 Once again in BTS6120 the partition number simply refers to the most significant twelve bits of a twenty four bit disk address and the OS 8 block number is the least significant twelve bits It s no more complicated than that 4 3 2 ID01 Handler The 1001 is the OS 8 handler for the SBC6120 IDE ATA disk It supports eight units IDAO through IDA7 a single page and may be assembled as either a system IDSY or non system IDNS handler The system handler version of the 1001 contains a secondary bootstrap that can be booted by the BTS6120 Boot command see section 5 8 3 The IDO1 is a simple handler that uses HD 6120 PRO instruction to invoke BTS6120 functions for low level IDE disk access and data transfer see section 6 5 BTS6120 implements a partition map which defines the partition number corresponding to each OS 8 1001 unit and when OS 8 program accesses 1001 unit BTS6120 uses this table to determine the upper twelve bits of the LBA At power on or after a MR command section 0 BTS6120 initializes this partition map so that unit 0 accesses partition 0 unit 1 accesses partition 1 and so on up through unit 7 and partition 7 This mapping remains in effect until it is changed by either the PM command section 5 8 5 or the Set IDE Disk Partition Mapping PRO funct
40. ction is also identical to PRO function 1 Read Write RAM Disk If this function fails then on return the LINK will be set and the contents of the drive s error register are in the AC If no IDE drive is attached to the SBC6120 then this call will always give the error return with the LINK set and 0377 in the AC A program can also test to see if an IDE drive is attached using the next function Get IDE Disk Size GET IDE Disk SIZE PRO function 5 will return the size of the IDE disk 03 09 2003 1 35 PM Page 40 6 7 6 8 6 9 Spare Time Gizmos SBC6120 User s Manual PRO call SBC6120 ROM firmware 5 function code for Get IDE disk size lt return with disk size in megabytes in gt The size of the IDE disk in megabytes is returned in the AC Zero will be returned in the AC if no IDE disk is attached This function has no error return SET IDE Disk PARTITION MAPPING PRO function 6 will set the IDE disk partition that is mapped to an OS 8 unit number TAD lt part gt load the partition number into the AC PRO call SBC6120 ROM firmware 6 function code for Set IDE disk partition lt unit gt 0S 8 unit to be changed 0 7 lt return gt After executing this function the Read Write IDE Disk function will reference the selected partition whenever this unit is accessed See section 4 3 ATA Disk Support for more information IMPORTANT If OS 8 has been booted from the IDE disk use care when re mapping unit
41. d DF Format IDE Disk The DF and RF commands will format an IDE disk partition or a RAM disk unit The names are a misnomer because there s nothing about either disk that needs formatting in the way a floppy does but this command does write and then read back every single block with a test pattern This serves the very useful function of testing the disk 19 For example 0122 160 is word 160 of block 1228 03 09 2003 1 35 PM Page 34 Spare Time Gizmos SBC6120 User s Manual It works in two passes Pass one of the formatter writes every block with a simple test pattern consisting of alternating words filled with the block number and its complement and pass two reads back every block and verifies that the test pattern written is still there If any block doesn t contain the data we expect then a Verification error message will be printed along with the failing page block number Although it s not too creative this pattern does do two things it guarantees that each block is unique so we can make sure the disk addressing is working and it does ensure that every bit gets tested with a zero and a one so we can make sure the data lines are working WARNING This command erases everything on the selected RAM disk unit or IDE disk partition Since this command is little on the dangerous it goes to the extraordinary length of asking for confirmation before doing anything Confirmation is nothing more than a single character it
42. d fail because of the soldering This is especially true of the SBC6120 it is not an easy project to solder The four layer PC board has internal power plans this makes it difficult to solder power pins because the internal planes act as a heat sink and draw the heat away The PC board was laid out with 8 and 8 design rules which means that the traces are only 8 mils that s 0 008 inches wide and in some places there is only 8 mils of air gap between adjacent traces or pads The SBC6120 is definitely not a learn to solder project if you ve never soldered a board like this before then it d be a good idea to find something cheaper to practice on When it comes to soldering having the proper tools makes all the difference A temperature controlled soldering station with a 30 mil tip will can be purchased for about 100 and will make the job much more pleasant The right solder is important too 63 37 solder is preferable to the traditional 60 40 because it has a slightly lower melting point and requires less heat You should not be using anything larger than 31 mil 0 031 inch diameter solder And finally you ll want a nice pair of wire cutters for trimming the leads on components after you ve soldered them Get the kind that s made for trimming wires on PC boards they have a special cutting face that cuts flush with the PC board without leaving any wire stubs sticking up 1 On more than one occasion hav
43. d the OS 8 keyboard monitor 4 4 1 ID01 and VMO 1 Primary Bootstrap The primary bootstrap for the SBC6120 RAM and IDE disks are six words loaded in locations 0 through 5 0000 6206 PRO execute a panel request 0001 0001 1 1 for RAM disk 4 for IDE disk 0002 0100 0100 read one page into field zero 0003 0000 0000 location zero 0004 0000 0000 from page block zero of the device 0005 7402 HLT should never get here If all goes well the HLT in location 5 is never executed it is over written by the secondary bootstrap code before BTS6120 returns from the PRO function Either device can be booted by depositing these six instructions in main memory with the D command section 5 2 3 and then 16 The one which you have to toggle in with the switches 03 09 2003 1 35 PM Page 20 4 5 Spare Time Gizmos SBC6120 User s Manual starting at location zero with the ST command section 5 5 1 but it normally such heroics are not necessary The SBC6120 B command section 5 8 3 does the same job with much less work 4 4 2 Boot Key The B section 5 8 3 command in BTS6120 actually bypasses the primary bootstrap step and simply reads block zero of the boot device into page zero field zero directly The VMO1 and IDO1 secondary bootstraps all contain a special key in words O through 5 the ones which would normally overwrite the primary bootstrap and BTS6120 looks for this key to identify a bootable volume If the key is found t
44. didates for shorts A few to watch out for are U18 pin 1 U16 pin 27 U15 pin 11 U13 pin 9 and there are several places inside J4 There are other places have traces running close to pins some of these are U5 pin 35 to trace running below pin U3 pin 1 to trace running above pin and U18 pin 1 to trace to right of the pin Some of the bypass caps are also very close to traces and when you nip the leads on these check that your cutters cut cleanly and don t cause shorts And finally be careful not to use too much solder on the pins excessive solder can wick up the pin to the top side of the board and cause invisible because they re hidden under the IC socket shorts there strongly advise using good high machined pin sockets for all ICs These sockets are admittedly expensive a 16 pin DIP socket might cost 50 cents and a 40 pin DIP more than dollar but they re worth it if you ever need to replace an IC Some people may object to the idea of putting a 25 cent 74HC74 IC into a 50 cent socket but it s not the IC you are protecting it s the PC board If you ever fry that 74HC74 and a single slip of the scope probe is all it takes then it will require significant skill and equipment to unsolder that dead IC without damaging the board With a socket it takes only a few seconds to pop out the dead one a pop in a new one The only possible exceptions to the socket everything rule are the two crystal oscillators These may be socketed if
45. discard the upper four bits of a twelve bit word and when reading these bits are undefined and should be masked off by the software Addressing the RAM disk 15 a little tricky since 2Mb memory requires a total of 21 address bits quite a bit more than a PDP 8 can manage RAM disk address bits 0 11 the low order bits contrary to the PDP 8 convention are supplied by the HD 6120 MA11 0 The remaining 7 bits needed by each 512K SRAM come from a special register the Disk Address Register which can be loaded via the LDAR IOT The final two bits needed by the DS1221 to select one of the four SRAM chips come from the HD 6120 EMAO and EMA1 EMA2 is not used at the moment Put more simply the data field selects the SRAM chip used the DAR selects the 4K byte bank within the chip and the normal memory address selects the individual byte within the bank IOT Function LDAR 6410 Load RAM disk address register Table 8 RAM Disk IOTs IDE INTERFACE In the SBC6120 the IDE interface is implemented by a standard 8255 PPI which gives us 24 bits of general purpose parallel I O PPI port A is connected the high byte DD8 DD15 of the IDE data bus and port B is connected to the low byte DDO DD7 Port C supplies IDE control signals according to the following table 11 Almost as big as a RK05J 03 09 2003 1 35 PM Page 14 3 6 Spare Time Gizmos SBC6120 User s Manual PPI IDE C0 C2 DAO 2 Device add
46. e accidentally connected 12V to the 5 input on the SBC6120 and although wish could say that was just testing and did it on purpose in truth it was simple stupidity have blown several of the fuses but never fried a chip Yes I m old enough to have built one or two missed their golden years though 03 09 2003 1 35 PM Page 4 Spare Time Gizmos SBC6120 User s Manual You ll want to wash the bare PC board before you start soldering to remove any grease or oils from fingerprints If you don t wash them off these oils will make the solder take longer to flow and will require more heat and flux to get a good solder joint prefer to use a mildly abrasive cleaner such as a Brillo pad or Comet cleanser with a sponge for cleaning They do a better job removing oils but remember to rub ightly heavy scrubbing will remove the plating or the silkscreen Lastly and most importantly make sure the board is completely dry before you start soldering Even a tiny amount of water left in a hole will turn to steam when soldering heat is applied and blow the solder right out of the hole If you have it compressed air or canned air is ideal for removing water from the holes and can be used to accelerate the drying process The SBC6120 PC board does not have a solder mask and you must use care to avoid solder bridges to adjacent traces and pads There are a few pins where vias come up close to a pad and these are especially likely can
47. emove J10 2 7 2 Baud Rate Jumpers J11 through J14 select the console baud rate according to this table Jumper Baud J11 38 400 J12 9 600 J13 1 200 J14 300 Table 4 Baud Rate Jumpers WARNING Only one of these jumpers should be installed at any time TEST POINTS Test point TP1 is connected to RESET L If you mount your SBC6120 in a box you can connect this point to a second RESET push button on the front panel The other side of the push button should be connected to ground This test point can also be used with an EPROM emulator to allow the system to be reset when new code is downloaded Test point TP3 is connected to ground and TP2 is connected to Vcc 5V They are convenient places to connect the ground lead of your scope probe or the power leads of your logic probe 03 09 2003 1 35 PM Page 9 3 1 Spare Time Gizmos SBC6120 User s Manual HARDWARE DESCRIPTION Besides the HD 6120 CPU the SBC6120 has gt 64KW that s 64K twelve bit words of RAM 32KW for panel memory and 32KW for conventional memory gt 8KW of EPROM which contains the BTS6120 firmware Up to 32KW of EPROM can be supported by the SBC6120 however the firmware currently uses only 8K gt Up to 2Mb real eight bit bytes this time of battery backed up non volatile SRAM which is bank switched and mapped into 6120 panel memory space This memory is normally used as RAM disk for OS 8 two megabytes being roughly
48. equivalent to one RK05 disk pack gt elaborate memory management system that controls the mapping of RAM EPROM and RAM disk into panel memory gt A real straight 8 compatible console terminal interface The logic for this interface is implemented in a GAL no 6121 is used and no software emulation is required gt IDE ATA disk interface implemented with an 8255 PPI and programmed I O Four LEDs used to show POST error codes Figure 3 SBC6120 Block Diagram PROCESSOR The HD 6120 is general purpose high speed CMOS 12 bit microprocessor designed to recognize the instruction set of Digital Equipment Corporation s PDP 8 E minicomputer Many Mistakes that caused endless software compatibility problems in all models of the DECmate 03 09 2003 1 35 PM Page 11 3 2 Spare Time Gizmos SBC6120 User s Manual architectural functional and processing enhancements have been designed into the 6120 such that it can provide much higher system performance than its predecessor the Intersil IM6100 The HD 6120 features include A completely PDP 8 E compatible instruction set Built in KM8E compatible memory management A separate control panel memory for a bootstrap monitor Two on chip stack pointers A 2 75us add cycle time with a 5 1MHz clock VVVVV MEMORY MANAGEMENT The SBC6120 has three memory subsystems 64K words of twelve bit RAM 8K words of 12 bit and up to 2Mb of 8 bit of SRAM wi
49. er CMOS SRAM Jameco 105380 Machined pin DIP socket 628512 U6 74HC373 JDR Octal D latch U1 Dallas Semi 051221 06F4235 Nonvolatile SRAM controller Spare Time Gizmos RAMDISK 1A PCB Express RAMDISK 1 REV A PC Board C1 C2 C3 C4 C5 0 1uF 50V mono ceramic capacitor 0 1 lead spacing Table 18 RAMDISK Parts List 03 09 2003 1 35 PM Page 48 Spare Time Gizmos SBC6120 User s Manual C SILK SCREEN 5402 C32 C31 C23 C30 m l m mjm ole ole m eenueen Sip NSOLE osanaaaasssus 111211555542 000009090908 000000000000 AZ IK EEE LEE LEN 2020000000060 y 03 09 2003 1 35 PM Page 49 Spare Time Gizmos SBC6120 User s Manual IOT REFERENCE IOT OPCODE G1 G2 co C1 SKIP BYTE DESCRIPTION CONSOLE TERMINAL KSF 6031 42 Skip if console receive is set section 3 3 KCC 6032 Clear console receive flag and KRS 6034 OR AC with console receive buffer KRB 6036 Read receive buffer into and clear the flag TSF 6041 Skip if console transmit flag is set TCF 6042 Clear transmit flag but not the TPC 6044 Load AC into transmit buffer but don t clear flag TLS 6046 Load into transmit buffer and clear the flag IDE INTERFACE 8255 PPI PRPA 6470 Read PPI port A section 3 5 PRPB 6
50. ficulty 2 2 3 GALs Three GALs are used in the SBC6120 two 22V10 types for IOT decoding and one 16V8 type for memory decoding Atmel ATF22V10 and ATF16V8 parts were used in the SBC6120 prototype because these devices are flash memory based and may be erased and reprogrammed any number of times however any GALs with the appropriate organization will work 2 2 4 EconoReset 051221 EconoReset comes in two versions one with a 5 Vec tolerance and another with a 1096 tolerance The 1096 version is recommended as the 5 version has a tendency to cause spurious RESETs whenever there is a slight drop in the V This situation is exacerbated by the picofuse which has sufficient internal resistance to drop 0 2 to 0 3 volts at the 300mA draw of the SBC6120 It will be made worse if you are using a 2 5 laptop style hard disk since these drives use 5V to power the motor Even though the disk isn t powered from the SBC6120 if you power both from the same supply it can cause a deep enough drop in V to reset the DS1221 when the drive spins up The 1096 version of the DS1221 provides a wide enough tolerance to avoid these problems 03 09 2003 1 35 PM Page 3 2 3 Spare Time Gizmos SBC6120 User s Manual 2 2 5 82055 PPI You must use at least 5 MHz version of the 82C55 as indicated by an A5 5 suffix slower parts will not work 2 2 6 LED display Please be aware that the quad LED display specified for D2 has internal d
51. field 1 Checksum 0135 5 2 7 WS Word Search Memory The ws command searches memory for a specific bit pattern It accepts up to 4 operands 1 the value to search for 2 the starting search address 3 the final search address and 4 a search mask All values except the first are optional and have appropriate defaults Any location in the specified range that matches the given value after being masked is typed out along with its address This command operates only on main memory and there is no equivalent for panel memory Formats gt WS vvvv search all of memory for the word vvvv gt WS vvvv aaaaa bbbbb search for vvvv between aaaaa and bbbbb gt WS vvvv aaaaa bbbbb mmmm search for the word vvvv between locations aaaaa and bbbbb using mmmm as search mask Examples gt WS 6031 search all of memory for KSF instructions 01045 6031 01207 6031 WS 6031 30000 33777 search words 0 3377 of field 3 for KSFs Search fails gt WS 6030 0 77777 7770 search memory for any keyboard IOTs 01042 6034 01045 6031 01106 6032 01207 6031 01212 6034 01214 6032 07616 6034 07621 6031 5 2 8 FM Fill Memory The FM command fills a range of memory locations with a constant This command operates only on main memory and there is no corresponding command for panel memory Formats vvvv fill all of memory with the constant vvvv 03 09 2003 1 35 PM Page 28 5 3 Spare Time Gizmos SBC6120 User s Manua
52. ge 0 the boot block of RAM disk unit 0 gt RD 0 0 0000 000 0302 0317 0317 0324 0000 6206 0001 0100 0000 010 7600 0001 7630 7402 6206 0001 0110 7600 0000 020 0000 7630 7402 6203 5425 7600 0000 0000 output deleted 0000 150 0000 0000 0000 0000 0000 0000 0000 0000 0000 160 4430 4430 0000 2220 0240 4430 4430 4440 0000 170 4440 4440 4440 4440 4440 4440 4440 0000 2001 5 8 2 RL RAM Disk Load and DL IDE Disk Load The DL and RL commands allow a disk to be downloaded over the console serial port The format of the data expected is identical that that generated by the RD and DD commands which makes it possible to upload a disk image to the PC and then later download the same image back to the SBC6120 Since all the data is simple printing ASCII text any terminal emulator program that can capture and replay the data will suffice These commands prompt for each line of data with a Terminal emulator programs for the PC can be set to look for this prompting character before transmitting the next line which eliminates the need to insert fixed delays to avoid overrunning the SBC6120 Since only printing ASCII characters are used in this protocol a download can be aborted at any time simply by typing a Control C There s no need for a timeout the way there is with loading paper tape images Formats gt RL u download data to RAM disk unit u gt DL download data to IDE disk partition pppp 5 8 3 RF Format RAM Disk an
53. hat the component side is up and the connectors are on your right then the following diagram shows the correct orientation for these capacitors C32 c31 C29 C30 MAX232 Capacitor C37 is also polarized however the correct orientation for it is shown on the silk screen FINAL CHECKOUT After you finish assembly apply power before installing any ICs Check that the power LED lights that 5 is present on the power pins of the IC sockets and if you soldered them in that the oscillators are running Next install all the chips except the precious 6120 and measure the 5V current lt should be around 250mA if it s more than 300mA you have a problem somewhere that you should fix before risking your CPU Lastly install the CPU being careful to disconnect the power first and careful to take precautions against static damage to the 6120 Verify that you have set your baud rate correctly refer to section 2 7 2 connect a terminal apply power and you should see the LEDs count down in the binary sequence 7 6 5 1 When the LEDs reach 1 you should see the BTS6120 sign on message SBC6120 ROM Monitor V211 Checksum 3525 6642 12 JUN 01 19 50 01 Copyright C 1983 2001 Spare Time Gizmos All rights reserved RAM OKB Battery FAIL IDE Not detected The POST will pause for a moment on 4 that s the memory test and it s normal for it to take a few seconds Also note that the POST
54. have any effect on the contents of main memory Format gt MR gt perform a master reset TERMINAL COMMANDS 5 6 1 TW Terminal Width The TW command sets the terminal screen width to the value of its argument which is a decimal number and must be in the range 32 to 255 BTS6120 will generate an automatic carriage return whenever an input or output line reaches the screen width 03 09 2003 1 35 PM Page 32 5 7 5 8 Spare Time Gizmos SBC6120 User s Manual Format gt IW nn gt set the terminal width to nn decimal 5 6 2 TP Terminal Page The TP command sets the terminal page size to the value of its argument in decimal which must be in the range 12 to 48 or zero BTS6120 will automatically pause terminal output whenever the specified number of lines is reached output will resume when the user presses Control Q see section 5 1 2 A page size of zero disables the automatic XOFF function Format gt nn set the console screen size to nn decimal LoAD DUMP COMMANDS 5 7 1 LP Load Paper tape The LP command loads a paper tape from the console terminal in standard PDP 8 BIN loader format If your console is actually an ASR 33 and you have a real PDP 8 paper tape then this will probably even work but a more likely situation is that you re using a PC with a terminal emulator and in that case the paper tape image can be downloaded from the PC s disk The loader accepts all standard BIN data frames including f
55. he SDASP 6411 5 Skip on IDE disk active section 3 5 POST n 644n Display POST code n section 4 1 SSLUCM 6412 Select SLU console mode device codes 03 04 SSLUSM 6413 Select SLU secondary mode device codes 36 37 77 If the RAM disk daughter board is not installed then this IOT is a no op which clears the AC DASP L 03 09 2003 1 35 PM Page 52
56. he RAM for all memory accesses and the EPROM is not used This is the normal mapping mode used after the ROM firmware initialization e Map 3 is the same as map 2 except that the RAM disk memory is enabled for all indirect accesses RAM disk memory is only eight bits wide and reads and writes to this memory space only store and return the lower byte of a twelve bit word This mode is used only while we re accessing the RAM disk IMPORTANT The memory mapping mode affects only HD 6120 control panel memory accesses Main memory is always mapped to RAM regardless of the mapping mode selected The EPROM is actually 16 bits wide but the hardware simply throws away the extra four bits 03 09 2003 1 35 PM Page 12 3 3 3 4 Spare Time Gizmos SBC6120 User s Manual CONSOLE TERMINAL The console terminal interface of the SBC6120 is software compatible with the traditional PDP 8 interface and is a proper subset of the KL8E The only difference between the SBC6120 and the KL8E are that the TFL KIE and TSK instructions are omitted from the SBC6120 Console interrupts are permanently enabled as they were in the original PDP 8 IOT Function KSF 6031 Skip ifthe console receive flag is set KCC 6032 Clear the receive flag and AC KRS 6034 OR AC with the receive buffer but don t clear the flag KRB 6036 Read the receive buffer into AC and clear the flag TSF 6041 Skip if the console transmit flag is set TCF 6042 Cle
57. hen BTS6120 simply jumps to main memory location 5 to start the secondary bootstrap and finish loading OS 8 This system should also work for any other non OS 8 system provided that it uses the same primary bootstrap shown above and that its secondary boot contains the special key in the first five words As long as the secondary bootstrap starts at offset 5 the remainder of its code is unimportant to BTS6120 and it can do anything it likes What s the magic key The letters BOOT in eight bit ASCII one character per word in locations 0 to 4 and a zero in location 5 LOADING OS 8 oNTO THE SBC6120 Now that you ve built your SBC6120 you re probably wondering how to get OS 8 loaded on it After all you can t very well put in your RX01 floppy or your 5 disk pack and boot it up There are at least four ways to get OS 8 onto the SBC6120 gt Usea PC to build an IDE disk with a bootable OS 8 image on it gt Download a bootable OS 8 image to the SBC6120 over the serial port gt Program an EPROM for the RAM disk board with a bootable OS 8 image gt Use the BTS6120 Bu Build command to build bootable media of these options will require that you have some form of PDP 8 emulator running on a PC The emulator must be able to run OS 8 and it must support emulation of the SBC6120 1001 IDE and or VMO1 RAM disk devices Not surprisingly the Spare Time Gizmos WinEight emulator fills all these requirements nicely Other emulators su
58. ield changes and correctly calculates and verifies the tape checksum If the checksum matches then the number of words loaded is printed but otherwise a checksum error message is generated When initially started this command ignores all input until two consecutive leader codes octal 200 are found which allows us to ignore any extra ASCII characters from the terminal emulator such as carriage returns Spaces etc Since we re using the real console the same one that you re typing commands on for input we have a problem in that we need some way to terminate loading Control C won t work since the BIN loader eats all eight bit characters A hardware reset isn t a good idea since the POST memory test will erase everything we ve loaded Instead the BIN loader has a timeout and if approximately five seconds pass without input the loader is terminated Format gt LP load a BIN format paper tape from the console IDE AND RAM Disk COMMANDS 5 8 1 RD RAM Disk Dump and DD IDE Disk Dum These commands dump one or more disk records in octal to the console What you get from DD or RD is exactly how the OS 8 device driver sees the disk data Each command accepts one two or three parameters The first is unit number for RAM Disk RD commands or the partition number for IDE Disk DD commands The second parameter is the number of the block to be dumped in octal If this number is omitted then the entire disk will be dumped which although
59. ion section 6 7 4 3 3 OS 8 PART Program The largest mass storage device supported by OS 8 is actually only 4095 blocks not 4096 and so the last block of every 2Mb partition is never used by OS 8 This block can however be accessed via the Read Write IDE disk PRO function section 6 5 and it can be used to store the 15 More correctly the actual OS 8 limit is 4095 blocks but there ll be more on that later 03 09 2003 1 35 PM Page 19 4 4 Spare Time Gizmos SBC6120 User s Manual name creation date and other information about that partition The OS 8 PART program uses this to allow partitions to be mounted on IDO1 logical units by name rather than partition number Named partitions are strictly a function of the OS 8 PART program and BTS6120 knows nothing about them OS 8 BOOTSTRAP BTS6120 contains a primary bootstrap for both the RAM disk and IDE disk devices and the OS 8 handlers for these devices VMO1 and 1001 contain a secondary bootstrap for OS 8 There is lots of documentation on how to write a device handler even a system handler for OS 8 but a description of how to make a bootable device is not easy to find Here s a brief summary The primary bootstrap for a device 9 normally loads cylinder 0 head 0 sector 0 which is the equivalent to OS 8 logical block zero into memory page zero field zero This contains the secondary bootstrap which is then started in some device specific way usually the primary
60. ion and the LINK will not be set in this instance If the unit number passed in the AC is greater than three then the LINK will be set to indicate an error and the AC cleared on return RAM Disk BATTERY STATUS PRO function 3 will return the status of the RAM disk Lithium backup battery PRO call the SBC6120 ROM firmware 3 function code for Get RAM disk battery status return with AC 1 if batteries are OK As long as either battery has sufficient voltage 1 will be return in the AC If both batteries have failed then zero is returned This call has no error return The backup battery status is tested by BTS6120 once immediately after power up and the result stored in a word of panel memory This call simply returns the value of that stored flag and does not cause the batteries to be tested again It isn t possible to monitor the battery status in real time READ WRITE IDE Disk PRO function 4 15 used to read or write the SBC6120 IDE disk PRO call the SBC6120 ROM firmware 4 function code for IDE disk I O lt argl gt R W bit page count buffer field and unit lt arg2 gt buffer address lt arg3 gt starting block number lt return with the LINK set if an error occurs gt The argument list for this function including the definition of arg1 is identical to a standard OS 8 device handler call Except for arg3 which specifies the disk address in blocks rather than pages the argument list for this fun
61. l vvvv aaaaa bbbbb fill all locations from aaaaa to bbbbb with vvvv Examples 7402 0 7777 fill all of field zero with HLT instructions gt E 1000 1001 01000 7402 7402 7402 7402 7402 7402 7402 7402 7777 0 77777 fill all of memory with 1 gt E 11000 11007 11000 7777 7777 7777 7777 7777 7777 7777 7777 5 2 9 CM Clear Memory Th command will clear a block of memory It is identical to the FM command with the exception that the fill value is always zero Formats gt clear all of memory gt CM aaaaa bbbbb clear all locations from aaaaa to bbbbb Example gt CM clear all of memory gt CK 0 77777 Checksum 0000 REGISTER COMMANDS 5 3 1 ER Examine Register The ER command examines either a single register when the register name is given as an argument or all registers when no argument is given Remember that this command is really examining the state of the main memory program that was saved when panel mode was last entered and not the actual contents of the 56120 registers now Formats gt ER xx gt print register xx xx can be AC MQ PC SR or PS gt ER gt print all registers Examples gt ER PC gt 1211 gt 1211 PS gt 5000 AC gt 0000 gt 0000 SP1 gt 0000 SP2 gt 0000 5 3 2 DR Deposit Register The DR command deposits a value in a register and both a register name and an octal value are required arguments Like the ER command this is
62. legal will take quite a while The third parameter is the count of pages for RAM disk or blocks for IDE disk to be dumped and if omitted this defaults to 1 For each IDE disk block dumped the output format consists of 33 lines of data where the first 32 lines all have this format block offset l data data data data data data data data 03 09 2003 1 35 PM Page 33 Spare Time Gizmos SBC6120 User s Manual The block and offset values give the physical position of the first data word on the line and are followed by exactly 8 words of data all in octal The 33rd line contains just a single octal number a checksum of all 256 words in the block The format for RAM disk data is the same with the exception that 128 word RAM disk pages only require 16 lines of data This format is the input that s accepted by the DL and RL commands which allows you to capture the output of a disk dump on a PC terminal emulator and then download the same data later to a different disk This is the primary motivation for the checksum it isn t too useful to humans but it will guard against errors in the upload download procedure Formats gt RD pppp cccc dump pages of RAM disk unit u starting at page pppp gt p bbbb cccc dump blocks of IDE partition p starting at block bbbb gt RD pppp gt dump page pppp of RAM disk unit u gt DD p gt dump all of IDE partition p 4095 blocks Example gt Dump pa
63. lost forever The minimum set of system components that BTS6120 monitor needs to have working before it can print a prompt and execute commands is the CPU the EPROM the RAM and the console terminal The SBC6120 has a three bit LED display see section 3 6 that can be set by the POST IOT After power on or a reset BTS6120 tests each critical system component and before each test it sets this LED display to a particular value If that test fails and BTS6120 crashes or halts the display remains at the last value set and indicates the cause of the failure The POST codes and their associated failure modes are shown in Table 12 03 09 2003 1 35 PM Page 17 4 2 4 3 Spare Time Gizmos SBC6120 User s Manual PO P1 P2 Code Failure On On On 7 CPU failure or CPU is not a HD6120 On On Off 6 Panel RAM bootstrap failure On Off On 5 ROM checksum failure On Off Off 4 Memory test failure Off On On 3 unused reserved for future hardware Off On Off 2 Console terminal failure Off Off On 1 Panel monitor BTS6120 running success Off Off Off 0 Main memory program running Table 12 POST Codes RAM Disk SUPPORT As described in section 3 4 the SBC6120 RAM disk hardware divides the address space of each SRAM chip up into banks of 4K bytes The BTS6120 firmware can fit 21 pages of 128 twelve bit words packed using the standard OS 8 three for two
64. lt arg3 gt starting page number not block number lt return with the LINK set if an error occurs gt The argument list for this function including the definition of argi is nearly identical to a standard OS 8 device handler call The sole exception is arg3 which gives the RAM disk address as a page number rather than an OS 8 block number Contrary to the usual OS 8 convention for handlers all RAM disk and addressing is in terms of 128 word pages rather than 256 word blocks If this function fails then the LINK will be set upon return and an error code contained in the AC AC Error 0001 Invalid unit number or SRAM chip not installed 0002 Page number too large Table 16 Read Write RAM Disk Error Codes 03 09 2003 1 35 PM Page 39 6 3 6 4 6 5 6 6 Spare Time Gizmos SBC6120 User s Manual GET RAM Disk SizE PRO function 2 will return the size of a RAM disk chip TAD unit load the desired RAM disk unit 0 3 PRO call the SBC6120 ROM firmware 2 function code for Get RAM Disk Size return with the RAM disk size in the AC The desired RAM disk unit from 0 to 3 should be passed in the AC and the usable size of the corresponding SRAM chip in 128 word pages is returned in the AC A 512K SRAM would for example return 268840 in the AC If there is no SRAM chip installed for the selected unit then zero will be returned in the AC this is not considered an error condit
65. nation address a single 15 bit number words from the starting source address to the ending source address are transferred to the corresponding words starting at the destination address Transfers may cross a field boundary and any number of fields may be copied at one time This command operates only on main memory and there is no corresponding block move command for panel memory Format gt BM aaaaa bbbbb ddddd move the block of memory from addresses aaaaa to bbbbb to the block starting at address ddddd Examples 00000 37777 40000 copy fields 0 through 3 to fields 4 through 7 0 7777 10000 copy all of field 0 to field 1 200 377 400 copy page 1 in the current data field to page 2 03 09 2003 1 35 PM Page 27 Spare Time Gizmos SBC6120 User s Manual 5 2 6 CK Checksum Memory This command will compute the checksum of all memory locations between the two addresses specified and the resulting twelve bit value is then printed on the terminal This is useful for testing memory comparing blocks of memory and so on The checksum algorithm used rotates the accumulator one bit between each word so blocks of memory with identical contents in different orders will give different results This command operates only on main memory and there is no corresponding command for panel memory Format gt CK aaaaa bbbbb checksum locations aaaaa through bbbbb Example gt CK 10000 10177 checksum all of page 0
66. o connect a long ribbon cable to this connector Pin Signal Type Pin Signal Type 1 vcc PWR 2 VCC PWR 3 RD SR L Oo 4 WR SR L O 5 SKIP L OD 6 BYTE READ L OD 7 CO L OD 8 L OD 9 INTREQ L OD 10 INTGNT L O 11 READ L O 12 IOCLR L O 13 WRITE L O 14 LXDAR L O 15 LOAD DAR O 16 DISK O 17 GND PWR 18 GND PWR 19 N C 20 N C 21 EMA2 O 22 N C 23 MA4 O 24 N C 25 MA5 O 26 MA3 O 27 MA6 O 28 MA2 O 29 MA7 O 30 O 31 MA8 O 32 MA1 O 33 MA9 O 34 B This signal is not connected to the PPI however it may be tested by the SDASP 64114 IOT Output driven by the SBC6120 Open drain input with a 10K pull up located on the SBC6120 7 Bi directional Tristate 03 09 2003 1 35 PM Page 8 2 7 2 8 Spare Time Gizmos SBC6120 User s Manual Pin Signal Type Pin Signal Type 35 EMAO 36 DX1 B 37 10 38 DX2 B 39 11 O 40 DX3 B 41 1 O 42 DX4 B 43 DX5 B 44 DX11 B 45 DX6 B 46 DX10 B 47 DX7 B 48 DX9 B 49 GND PWR 50 DX8 B Table 3 Connector J4 JUMPERS 2 7 1 Break Enable J10 causes the 6120 5 CPREQ input to be asserted whenever a framing error is detected on the console port This allows you to break into the SBC6120 ROM monitor at any time simply by pressing the BREAK key on the console terminal To disable this feature r
67. r s Manual 5 1 4 BREAK If jumper J10 is installed see 2 7 1 then a framing error on the console port caused when the terminal sends a BREAK will immediately enter control panel mode SBC6120 will print a message similar to this one Break at 01211 gt 1211 5 gt 5000 gt 0000 0 gt 0000 SP1 gt 0000 SP2 gt 0000 gt If you pressed BREAK by accident you can usually use the C command to continue at this point and no harm will be done 5 1 5 Command Separator The semicolon character may be used as a separator between multiple commands on the same line Format gt aa bb cc dd 1 5 1 6 Comment The exclamation may be used as a comment character Any text after the exclamation up to the end of the line is ignored Format gt lany text MEMORY COMMANDS 5 2 1 E Examine Main Memory The E command allows the user to examine the contents of main memory in octal either one word at a time or an entire range of addresses at once In the latter case a memory dump 15 printed with eight PDP 8 words per line Formats gt E faaaa gt examine location aaaa field gt E aaaa gt examine location aaaa of the current data field gt E aaaaa bbbbb gt examine locations aaaaa to bbbbb gt E aaaaa bbbbb examine several memory locations at once Examples gt E 1234 31234 3145 gt E 01234 01234 2213 gt E 71000 72000 71000 7602 7105 6040 5100 1500 7777 76
68. r the SBC6120 is contained in Appendix B and with the exception of the HD6120 CPU all parts are common modern devices that should be readily available Most part values are non critical and substitutions should not be a problem however when changing connectors or switches use care that the replacements will fit the footprint on the PC board The SBC6120 is intended to use all CMOS devices Be sure to use 74HC parts for all 74xx logic CMOS 22V10 and 16V8 GALs 27C64 or 27C256 CMOS 5 and a CMOS 82C55 PPI Be particularly careful of the latter since NMOS 8255s are very common 2 2 1 SRAMs The HM6208 SRAMs used in the SBC6120 were originally intended for use as cache memories with Intel 486 processors and are available in 25 35 and 45 ns speeds All of these are ridiculously fast by HD 6120 standards and any version of the HM6208 may be used 2 2 2 EPROMs Two EPROMs are used to hold the BTS6120 ROM monitor and bootstrap Either 8K byte 27C64 style or 32K byte 27C256 style EPROMs may be used without any circuit changes or jumper settings however be warned that not all 27C64 EPROMS will work in this circuit Those which define as a don t care during read will work fine however those which require that be held at V during reading will not work In particular AMD AM27C64 EPROMSs work fine National NM27C64 EPROMs do not This problem applies only to 8K EPROMs all makes of 32K 27C256 EPROMSs should work without dif
69. really changing the saved state of the main memory program and not the current BTS6120 registers Any register values set with this command will be used after the next P C TR SI command 03 09 2003 1 35 PM Page 29 5 4 Spare Time Gizmos SBC6120 User s Manual Format gt DR xx yyyy deposit yyyy into register xx BREAKPOINT COMMANDS 5 4 1 BL List Breakpoints This command will list all the breakpoints that are currently set It has operands Format gt BL gt list all the currently set breakpoints 5 4 2 BP Break Point The BP command sets a breakpoint in the main memory program It requires a single argument giving the 15 bit address where the breakpoint is to be set WARNING It is not possible to set a breakpoint at location zero in any field BTS6120 uses zero as a marker for an unused breakpoint table entry Formats gt BP faaaa seta breakpoint at location faaaa gt BP set breakpoint at aaaa in the current instruction field Examples gt BP 07605 set a breakpoint at location 7605 field 0 gt BP 7605 1 gt BL 07605 0000 17605 0000 5 4 3 BR Remove Breakpoint The BR command removes a breakpoint at a specific address or if no argument is given removes all breakpoints Formats gt BR remove all breakpoints gt BR aaaaa gt remove only the breakpoint at location aaaaa Examples gt BR 17605 remove the breakpoint at location 7605 field 1 gt BL 07605 0
70. ress select c3 DIOR read DIOW write ca RESET ce CS1Fx Chip select for the 1Fx register space G7 CS3Fx Chip select for the 3Fx register space Table 9 IDE Control Signals One nice feature of the 8255 is that it allows bits in port C to be individually set or reset simply by writing the correct command word to the control register it s not necessary to read the port do an AND or OR and write it back We can use this feature to easily toggle the DIOR and DIOW lines with a single PWCR IOT The HD 6120 can access the 8255 PPI by standard 1075 IOT Function PRPA 6470 Read PPI Port A PRPB 6471 Read PPI Port B PRPC 6472 Read PPI Port C PWPA 6474 Write PPI Port A and clear the AC PWPB 6475 Write PPI Port B and clear the AC PWPC 6476 Write PPI Port C and clear the AC PWCR 6477 Write the PPI control register and clear the Table 10 8255 PPI IOTs POST Cope DISPLAY The SBC6120 contains a row of four LEDs next to the RESET switch The leftmost of these LEDs is a power indicator and is always lighted as long as 5V is applied The remaining three LEDs may be turned on and off by the software via the POST IOT and are used to display the results of the Power On Self Test see section 4 1 4 9 _0 iv Figure 5 POST Code LEDs IOT Function POST 644n Display POST code n Table 11 POST
71. ropping resistors Be sure you do not accidentally substitute a part without these resistors 2 2 7 Fuse The picofuse F1 and the zener diode D1 are there to protect you against accidental over voltage or reverse polarity of the power supply Yes it will work without them but they re cheap insurance and I strongly recommend you use them If you decide to omit the fuse remember that you must replace it with a wire jumper you can t simply leave it open 2 2 8 Oscillators The SBC6120 uses two TTL oscillators one to generate the baud rate clock for the console UART and another to generate the CPU clock The baud rate generator U23 must always be exactly 4 9152 MHz if we are to generate standard baud rates U1 generates the CPU clock and should nominally be 5 0 MHz These oscillators come in two versions one with an ENABLE pin and one without and either version may be used in the SBC6120 Harris specified the HD 6120 to work up to a maximum clock frequency of 5 1MHz however DEC actually ran the DECmates at 8 MHz Whether they were using specially selected parts or all 6120s would go this fast have no way of knowing but have regularly run my SBC6120 at 8 MHz without problems This can easily be changed by substituting an 8 MHz oscillator for U1 SOCKETS AND SOLDERING Every kit that have ever built all the way from the legendary Heathkit on down has always said that 9096 of the kits that don t work after they re assemble
72. st transmission errors however BTS6120 does not implement any special protocol or handshaking e g X Modem or Kermit for transferring the text The PC software must be careful therefore not to send data faster than the SBC6120 can process it BTS6120 prompts for each new record with a character and the PC terminal emulation software should wait for this prompt before transmitting each line 03 09 2003 1 35 PM Page 22 Spare Time Gizmos SBC6120 User s Manual The typical Kermit commands used to download a disk image to the SBC6120 set port coml set modem type direct set baud 9600 set flow none set handshake none set carrier watch off set file type text set transmit prompt 58 transmit system txt Other PC communications programs will no doubt work equally well it s just a matter of figuring out the appropriate settings for your favorite one 4 5 3 Program an EPROM for the RAM disk board The SBC6120 RAM disk daughter board will allow either a 27C010 128k x 8 or 27C040 512k x 8 EPROM to be used in place of any SRAM chip and the BTS6120 firmware simply treats the corresponding OS 8 VMO1 device as write protected BTS6120 contains some special processing in the VMO1 assist firmware which allows OS 8 to run from a write protected system device by using spare panel RAM to store system scratch blocks Programming an EPROM the SBC6120 RAM disk couldn t be easier the VMO1 image files produced by the WinEight
73. th a battery backup for a RAM disk The HD 6120 on the other hand has only two memory spaces panel memory and main memory and each of these is limited to 32K words The EPROM is a further problem because the PDP 8 instruction set makes it difficult if not impossible to get by without some read write memory in every 4K field The SBC6120 implements a simple memory mapping scheme to allow all three memory subsystems to fit in the available address space The memory map in use is selected by four IOT instructions MMO MM1 MM2 and what else MM3 Memory map changes take place immediately with the next instruction fetch there s no delay until the next JMP the way there is with a CIF instruction IOT Function MMO 6400 Select memory map 0 MM1 6401 Select memory map 1 MM2 6402 Select memory map 2 MM3 6403 Select memory map 3 Table 5 Memory Mapping IOTs The four memory maps implemented by the SBC6120 are e 0 uses the EPROM for all direct memory accesses including instruction fetch and uses the RAM for all indirect memory accesses This is the mapping mode selected by the hardware after power on or a reset e Map 1 uses the RAM for all direct memory accesses including instruction fetch and uses the for all indirect memory references This mode 15 the complement of map 0 and it s used by the ROM firmware initialization code to copy the EPROM contents to RAM e Map 2 uses t
74. that unit and with two arguments PM will change the mapping of that unit 03 09 2003 1 35 PM Page 35 5 9 5 10 Spare Time Gizmos SBC6120 User s Manual Formats gt PM u pppp map OS 8 IDO1 unit uto IDE partition pppp gt PM u display the mapping for unit u gt display the mapping for all units 5 8 6 PC Partition Co The PC command copies every block from one partition to another thus making the destination partition an identical copy of the source It is a convenient way to create backups of OS 8 partitions but use it carefully since everything in the destination partition will be over written Formats gt 5555 dddd copy partition 5555 to partition dddd MISCELLANEOUS COMMANDS 5 9 1 H Help The H command generates a simple list of all monitor commands and a brief one line help message for each The whole list is quite long and it may be useful to set the terminal page size see TP section 5 6 2 first Format gt H 5 9 2 RP Repeat This command repeats the remainder of the command line and it accepts an optional argument that specifies the number of times to repeat in decimal The range for this argument is 1 to 2047 and if omitted it defaults to 2047 Any error or a Control C will terminate the repetition prematurely WARNING Repeat commands may not be nested Formats gt RP nn bb repeat commands bb times aa bb repeat commands aa
75. where as 0010 would reference field 1 of main memory The second and fourth 03 09 2003 1 35 PM Page 41 Spare Time Gizmos SBC6120 User s Manual arguments define a specific starting memory address for the source and destination and argument five gives the total number of words to copy A word count of zero copies a full 4K field IMPORTANT If the word count plus the starting address exceeds 4K then this function will wrap around within the same field It will not roll over to the next field This function has no error return 03 09 2003 1 35 PM Page 42 Spare Time Gizmos SBC6120 User s Manual BUILDING OS 8 FOR THE SBC6120 This appendix describes the procedure used to install the SBC6120 1001 device handler into a standard OS 8 system and build a bootable disk image In this example we will start with an OS 8 image that was originally built with RX01 and RKO5 support All of the activities described in this appendix take place on a PC using a PDP 8 emulator such as WinEight and the result is 1001 image which can then be downloaded to the SBC6120 refer to section 4 5 Although this Appendix does not discuss it the technique for building 01 system is essentially the same after making the obvious changes to the device handler names 1 Edit your copy of the IDO1 PA file to ensure that the line which reads SYS 1 is not commented out The is the comment character in PAL8 so if the line appears as sYs
76. will fail on the console UART test 2 if you ve forgotten to install one of the baud rate jumpers J11 J14 03 09 2003 1 35 PM Page 6 2 6 Spare Time Gizmos SBC6120 User s Manual CONNECTORS 2 6 1 Power J1 is the main power connector and is compatible with a standard PC floppy hard disk power cable The following illustration shows the pin out of the power connector if you hold the SBC6120 board with the component side up and the rear connectors facing you Figure 2 Connector J1 Power consumption for the SBC6120 is less than one watt approximately 175 mA at 5V Fuse F1 and Zener diode D1 protect the SBC6120 from reverse polarity and over voltage on the 5V supply The SBC6120 does not use 12V and it is unconnected on the board 2 6 2 IDE J2 is used to connect an IDE hard disk and like J1 its configuration is compatible with the PC equivalent A standard 40 pin IDE ribbon cable may be used to connect this connector to the hard disk If a hard disk is not to be used with the SBC6120 then J2 may be used as a general purpose twenty four bit parallel I O interface Pins 1 23 25 37 and 38 are inverted by the 74HC04 on the SBC6120 and can be used only as outputs but the remaining pins may configured for either input or output by programming the 8255 PPI appropriately Pin Signal PPI Pin Signal PPI 1 DRESET L PC5 2 GND 3 DD7 PB7 4 DD8 PAO 5 DD6 PB
77. you wish but because of their height they will extend far above the other ICs and because of their metal cans they may short to any daughter boards mounted on the expansion connector If you do decide to socket them put a piece of electrical tape over them for insulation When soldering IC sockets and connectors especially the larger ones start by holding the part tightly to the board and then soldering only two pins on diagonal corners This will hold the part in place temporarily while you turn the board over and make sure the part is flush against the PC board If it isn t then apply pressure to the part while using your iron to re melt the solder on the closest pin The worst thing is to solder all 40 pins on a connector only to turn it over and find that its all skewed It s pretty much impossible to desolder all those pins and repair the error at that point Lastly clean the board again after you re finished soldering by using a commercial flux remover or if you ve used a solder with water soluble flux by washing with a toothbrush and warm water Some water soluble fluxes are corrosive in the long term and should not be left on the board Traditional rosin fluxes won t actually hurt anything but the residue obscures the traces and makes it harder to find shorts Make sure everything is completely dry before you begin installing parts in the sockets once again compressed air can be used to accelerate the drying process Please don t
78. zero This function will return with the LINK set if the unit number is greater than 7 No range checking is done on the partition number to ensure that it fits within the disk size if it does not I O errors will occur when the unit is accessed GET IDE Disk PARTITION MAPPING PRO function 7 will return the IDE disk partition that is mapped to an OS 8 unit number PRO call SBC6120 ROM firmware 7 function code for Get IDE disk partition unit 05 8 unit 0 7 return with partition number in the AC The number of IDE disk partition associated with the selected unit number will be returned in the AC If the unit number is greater than 7 then the LINK will be set and the AC cleared on return CoPY MEMORY PRO function 104 will copy up to of memory any location in main or panel memory to any other location in main or panel memory PRO call SBC6120 ROM firmware 10 function code for copy memory lt s0n0 gt source field and memory space lt address gt source address lt s0n0 gt destination field and memory space lt address gt destination address lt word count gt number of words to be transferred lt return gt The first and third arguments to this function specify a field number from 0 to 7 in bits 6 to 8 of the word and memory space flag in bit O This flag should be set to reference panel memory and cleared for main memory For example a value of 4050 would reference field 5 of panel memory

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