THE ROTRONICS WAFADRIVE
Contents
1. at 19200 Baud Output swing 10V p p nominal The peripheral should be adjusted to conform with this As far as the Baud rate is concerned choose the highest one that your peripheral will support Avoid using the higher Baud rates with long cables however 23 Rotronics Wafadrive Manual doc CONNECTING PERIPHERALS At the rear of the Wafadrive unit are three sets of connections The largest of these is the familiar Spectrum expansion bus The smallest is the RS232 serial port and the centre one is the Centronics port To connect peripherals to the Wafadrive you will require a lead terminated at each end with the appropriate connector If you are handy with a soldering iron it is possible to make your own by referring to the peripheral manual and the connection details below Generally however it is simpler safer and cheaper to buy a ready made lead A suitable one is available through your ROTRONICS dealer The edge connectors are depicted below viewed from the rear of the unit CENTRONICS Al A2 A3 A4 A5 A6 AT A8 AY A10 All A12 A13 Bl B2 B3 B4 B5 Bo B7 B8 B9 B10 BIT BIZ B13 RS232 Al A2 A3 A4 A5 B1 B2 B3 B4 B5 These are usually connected as follows CENTRONICS INTERFACE signal edge connector peripheral connector Ground A1 A2 A13 B1 13 16 17 19 30 Data strobe A4 1 Busy A3 11 Data 0 A12 2 Data 1 All 3 Data 2 A10 4 Data 3 A9 5 Data2. d filename Merges specified BASIC program with that currently stored in memory MOVE d filenamel TO d filename2 Makes a copy of file specified in filename optionally giving it the name specified in filename2 Wildcard facility also operates with MOVE allowing entire wafer contents to be copied if required NEW Clears BASIC program and also resets Wafadrive Operating System freeing reserved RAM NEW Initialises the Wafadrive Operating System reserving around 2K bytes for the directories and extended system variables NEW Clears the BASIC program area without resetting the Wafadrive Operating System OPEN stream channel Opens the specified stream and assigns it to the specified channel OPEN stream port Opens the specified stream and assigns it to the specified port channel OPEN stream d filename Open the specified stream and assign it to a data file channel If the file is a new one the channel is opened as an output channel ready for writing If the file already exists the channel is opened as an input channel ready for reading PRINT stream string data variables Sends string or numeric data to previously opened output stream If sending to a data file channel this must be configured as an output channel SAVE d filename LINE run Saves BASIC program in memory to drive specified Error report if file already exists Optional LINE suffix gives auto run facility upon loading SAV
3. 4 130 NEXT n 140 CLOSE 4 For simplicity the above program cheats a little Usually one would write the number of entries into the file or terminate the data with a control character to enable the correct number of entries to be read back If an attempt is made to read more entries than the file contains the program will stop with an End of file error report The user would then have to close the file before the wafer could be accessed again 21 Rotronics Wafadrive Manual doc As an example of how data files are used let us consider a group of names and exam results to be stored on wafer for reading back at a later date This program illustrates the way in which this can be accomplished 10 REM writ result 20 DATA 5 RESULTS 31 12 84 FRED 76 BILL 19 JOHN 82 ALISON 84 COLIN 64 30 OPEN 4 a results 01 40 READ c h PRINT 4 c h 100 FOR t 1 TOc 110 READ n m 120 PRINT 4 n m 130 NEXT t 200 CLOSE 4 210 STOP A program to read the data back in could take the form 500 REM read result 510 OPEN 4 a results 01 520 INPUT 4 c h 530 DIM n c 15 DIM m c 540 FOR t 1 TO c 550 INPUT 4 n t m t 560 NEXT t 570 CLOSE 4 600 REM display 610 PRINT h PRINT 620 FOR t 1 TOc 630 PRINT n t m t 640 NEXT t COPYING FILES Just as with programs it is important to take back up copies of files to guard against accidental erasure Overwriting or loss The obvious way to do this would be
4. Also closes any opened data file channels CLOSE stream Closes stream previously opened using OPEN If any of the streams 0 3 are specified these are all set to their default values The use of CLOSE is preferred when the Wafadrive is in operation CLOSE stream Closes stream previously opened using OPEN or OPEN Closing streams assigned to data file output channels causes the file to be stored on wafer and the directory to be updated CLS Clears the screen but also resets the attributes to PAPER 7 white BORDER 7 INK 0 black ERASE d filename Removes the specified file entry from the wafer treeing the reclaimed sectors for subsequent use Wildcard facility operates with ERASE FORMAT R baudrate Sets the RS232 transmit receive data rate The default value is 1200 baud FORMAT d wafername Used to prepare blank wafers ready for use Tape is completely erased of files and wafer is named INKEY stream variables Reads next single character from previously opened input channel via assigned stream INPUT stream variables Reads data from previously opened input channel via assigned stream 33 Rotronics Wafadrive Manual doc LIST stream line Lists program starting at optional line number to specified stream LOAD d filename Loads specified program irrespective of whether it is BASIC or machine code LOAD alone loads first program in directory of wafer in default drive MERGE
5. Attempting use MERGE with machine code files will result in a Wrong file type error report 15 Rotronics Wafadrive Manual doc COPYING PROGRAMS It is important to make back up copies of your files to guard against accidental erasure overwriting or loss The obvious way to do this would be to load each program individually then re save it onto the back up wafer The fact that the Wafadrive is a twin drive unit would obviously help here Even so if more than one or two files are involved it can be a tedious process The Wafadrive has a facility which makes the copying of files much easier It takes the form MOVE a filenamel TO b filename2 In this case A is the source drive and B the destination drive As usual the default drive specifier may be omitted If a second file name is not given the copy will take the same name as the original Files can be copied onto the same wafer but only if the copies are given names which do not already appear in the wafer s directory As with ERASE MOVE also includes the very useful wildcard facility For example MOVE a te TO b copies all files begining with TE from drive A to drive B Also MOVE a TO b copies all files from A to B MOVE does not affect any program in memory as the files are copied a sector at a time via a read write buffer If there is a large amount of information to be copied the process may take a few minutes Copying the entire contents of a 128K
6. in Kilobytes 5 The number of files on the wafer 6 The size of the wafer in Kilobytes 7 The spare capacity left on the wafer in Kilobytes Of course there are no files on the wafer as yet because it has just been formatted Once a wafer has been accessed the directory will be stored in the computer s memory To demonstrate this perform CAT again This time the border flashes very briefly and the directory re appears almost immediately The directory of a wafer in drive B is examined in exactly the same way just change the drive specifier to b upper or lower case The maximum number of files that can be held in the directory is 32 although 16K wafers are physically limited to 16 separate files If a long directory causes the screen to overflow the message scroll will appear the same as with a program listing Incidentally if you press the N key when asked scroll you will get the message BREAK CONT repeats as usual If you then enter CONTINUE expecting to see the rest of the directory you will be disappointed The computer will lock up although BREAK will restore control This is not the fault of the Wafadrive system the same happens with ordinary program listings See chapter 2 in the BASIC Programming Manual The Wafadrive system maintains a default drive This allows the drive specifier to be dropped from Wafadrive commands when referring to a specific drive When the system is first initialised dr
7. 0008 H is called the Spectrum ROM is disabled the Wafadrive ROM is paged in and control passes to the Wafadrive Operating System The above address is the location of the Spectrum s error handling routine which is called whenever a BASIC syntax error occurs either during program entry or execution So whenever a syntax error occur when the Wafadrive is connected the Wafadrive ROM is paged in to deal with it A check is made to determine whether or not the error is caused by an EBASIC command being encountered and the system is made to behave accordingly Genuine syntax errors are dealt with in the normal manner EBASIC commands are either accepted into the program or executed depending upon whether the error occurs during program entry or execution The Spectrum ROM is then paged back in 27 Rotronics Wafadrive Manual doc The hardware which controls the ROM paging is controlled by Z80 IN instruction A little thought reveals that when control is passed pack from the Wafadrive to the Spectrum ROM the appropriate instructions to perform this cannot be incorporated into the Wafadrive ROM Instead a short routine in RAM is set up in the extended system variables area to perform this function The syntax checking routine is accessed via a vector in RAM see appendix 3 This can be altered so that special custom commands can be written in machine code and added to Spectrum BASIC It may be of interest to know how the main commands whi
8. 30 31 35 36 37 38 39 48 52 53 54 59 62 36 62 48 36 62 44 S SAVE saving S screen channel Screen SCREEN scroll Sector Serial Servicing Splice Stop bits Streams STROBE System variables T Terminal Tokens TXD Vv Vector VERIFY verifying W Wildcard Word processor Write file Write protect Rotronics Wafadrive Manual doc 19 20 22 23 24 43 53 54 27 29 30 54 10 27 23 16 13 31 41 43 47 51 58 60 61 see RS232 8 41 36 27 28 29 30 31 32 33 38 48 49 51 52 53 54 59 37 59 60 62 9 41 42 52 55 57 58 60 39 38 36 62 42 20 24 43 47 49 53 21 25 51 52 7 48 15 47 61 45
9. RND CHR 134 140 NEXT n followed by MERGE a colours whereupon the two programs will be combined as normal You can merge an auto run BASIC program The resultant program will not auto run when merging is completed 13 Rotronics Wafadrive Manual doc SAVING USING AN EXISTING FILENAME Normally if you try to save a program using a file name that already appears in the wafer directory a File exists error message results and the program will not be saved This is to prevent programs being accidentally overwritten Sometimes however we may want any files of the same name to be overwritten For instance when developing a program on a small wafer a cycle of two programs can be used to avoid having to repeatedly erase redundant programs whilst retaining the last edited version as a back up In these circumstances we use a variation on the SAVE command SAVE At the moment if you have been following the examples given you will have a program in memory as a result of merging the two colours programs We can cause this version to be saved instead of the original program thus SAVE a colours The program will be saved and the original version will be lost As a general rule use SAVE which of course protects against inadvertent overwriting of programs Use SAVE with care and only when you are sure that there is no risk to anything of value stored on the wafer Protected files cannot be overwritten Attempting to u
10. sector is reserved for the directory and so the total program storage available is 1K less than the capacity of the wafer If you enter the FORMAT command in error you will usually have enough time to BREAK before the wafer starts to be erased Since up to four passes round the tape are required during formatting it is a relatively lengthy process This is not really important since it is not often performed more than once or twice during the life of a wafer The formatting process should now be completed and the wafer is ready for use The system will display the wafer capacity and whether any errors occurred during formatting No errors should occur If they do it could be a sign that the wafer is damaged or worn or that the drive read write head is in need of cleaning try again on the other drive Wafers which consistently give trouble during formatting should be discarded or at the very least treated with suspicion Rotronics Wafadrive Manual doc PROTECTING AGAINST ACCIDENTAL ERASURE Like cassettes and disks wafers may be protected against accidental erasure or overwriting of stored data This is done by removing the write protect tab which is on the left hand side of the wafer as it is inserted in the drive The original read write status of the wafer may be restored by covering the recess with a piece of tape Wafers cannot be formatted if the write protect tab has been removed Some pre duplicated wafers will not have
11. the write protect tab removed The programs on these wafers will usually have been recorded so that they cannot normally be erased or overwritten although they will not be immune from formatting MAINTENANCE The Wafadrive unit requires no more maintenance than does a conventional tape recorder The main point to observe is that the read write heads are kept clean so as to prevent loss of data The heads should be cleaned at intervals of 500 passes or so It is performed simply by wiping with a clean cotton tipped stick of the type used to clean babies important little places or by means of a special head cleaning wafer Use no cleaning fluid Rotronics Wafadrive Manual doc THE DIRECTORY A directory of files is maintained on each formatted wafer Every time a program is added to or deleted from wafer the directory is updated automatically When loading programs the system first examines the directory to determine whether or not the file is stored on the wafer and if so its location DISPLAYING THE DIRECTORY To look at the directory or catalogue of the wafer you have just formatted make sure it is inserted in drive A and enter CAT a The drive will start up the border will flash and after a short while the screen will display 1 The drive A in this case and the wafer name 2 A list of names of the files stored on the wafer 3 The type of each file program data or machine code 4 The size of each file
12. to read in each file individually then re write it onto the back up wafer This is not a very convenient solution so you will be glad to know that the MOVE command works with data files in exactly the same way as programs When copying no distinction is made between file types See chapter 5 if you need to refresh your memory about MOVE 22 Rotronics Wafadrive Manual doc CENTRONICS AND RS232 INTERFACES The Wafadrive is capable of driving most devices that are compatible with the Centronics parallel and RS232 serial interface standards Although primarily intended to allow commercially available software to communicate with printers modems and other computers users can also utilise the facility for their own purposes to reproduce text and produce program listings for example THE CENTRONICS INTERFACE The Centronics interface is a unidirectional one it can only transmit data from the host the Wafadrive to the peripheral normally a printer It is referred to as a parallel interface because data is sent a byte at a time along eight wires Since most microprocessors work a byte at a time it is relatively simple to implement at both the printer and computer end The Wafadrive provides an eleven wire implementation of the Centronics standard supplying the signals required by the vast majority of popular printers The parallel port may also be connected to a joystick via a simple adaptor Most of the software available o
13. which again is about 1K bytes in size This is created in memory when a data file channel is opened for input or output using the OPEN command There are also buffers created when streams are opened to the RS232 and Centronics ports These however consume just 11 bytes each 38 Rotronics Wafadrive Manual doc CONTROL PORTS There are several ports which the Wafadrive uses to control internal functions and access the communications interfaces Probably the most useful of these are the motor control and Centronics ports The RS232 port is not likely to be of very much use in this context and is not described here It should be noted that it is possible to damage the Wafadrive circuitry and possibly also the computer by wrongly connecting the external lines Only connect your own devices to the Wafadrive if you are absolutely sure of what you are doing The Wafadrive guarantee does not cover repairs to caused by misuse The Centronics port is essentially an eight bit output port plus two handshake lines one input BUSY one output STROBE If you are knowledgeable about electronics it can be used for general control D to A A to D etc If you are going to experiment with it regularly it is recommended that you connect via an optically coupled buffer to minimise the possibility of accidental damage The eight bit port can be written to in BASIC using the expression LET x IN 14 256 byte Where byte is the value to be output
14. with the file extension PRG to Indicate that it is a BASIC program Also shown is the file size rounded up to the nearest Kilobyte When saving a program using SAVE a File exists error message will be displayed if a file of the same name already exists on the wafer Note that there is no direct equivalent of the cassette SAVE DATA command This function is performed in a different manner on the Wafadrive see chapter 7 11 Rotronics Wafadrive Manual doc VERIFYING The program can be verified by entering VERIFY a colours Note that the file name may be specified in upper or lower case The file extension is only something which appears in the directory It is not part of the program name and should not be included in Wafadrive commands The command VERIFY b checks the program against the first program appearing in the directory of the specified drive in this case drive B and VERIFY checks it against the first program appearing in the directory of the default drive The entries in the wafer directory are in chronological order so the first entry in the directory is always the earliest file to be stored on the wafer LOADING Clear the program from the computer using NEW Now enter LOAD a colours The program can be listed to check that it has been fetched correctly The same comments apply to loading as to verifying for example LOAD causes the first program that appears in the directory of t
15. you may know already that some manipulation of streams is possible on the basic Spectrum Information is sent to the screen and received from the keyboard by means of the PRINT and INPUT statements respectively In a similar fashion PRINT and INPUT are also used to send and receive data to from streams The commands are simply suffixed with the symbol and the stream identifier thus PRINT 2 The ROTRONICS Wafadrive INPUT 0 a INPUT is of little use with the unexpanded Spectrum since there is only one input channel the keyboard We can have some fun with PRINT however since all three channels are capable of output 17 Rotronics Wafadrive Manual doc The PRINT and LPRINT commands can in fact be thought of as abbreviations of PRINT 2 and PRINT 3 remember that stream 2 is assigned to the screen and stream 3 to the printer If you have a Sinclair printer plug it in and run this program 10 LET a The ROTRONICS Wafadrive 20 PRINT 1 a 30 PRINT 2 a 3 a 40 PAUSE 0 The message will appear at the top of the screen at the bottom of the screen and also on the printer The PAUSE statement prevents the bottom line being overwritten by the OK report Line 30 illustrates the fact that than one stream can be included in a PRINT statement The program will also work in exactly the same way if LPRINT is substituted for PRINT The same principles apply to other I O statements such as LIST LLIST INPUT and INKEY The specia
16. 4 A8 6 Data 5 A7 7 Data 6 A6 8 Data 7 A5 9 RS232 INTERFACE signal edge connector peripheral connector Ground A1 B1 5 1 7 RXD A2 2 TXD AS 3 RTS A4 4 CTS A3 5 24 Rotronics Wafadrive Manual doc Further information will be found in your peripheral handbook If making your own lead it is wise to leave the B side contacts unconnected so as to prevent possible damage by wrong insertion of the connector Ensure that the power is disconnected from the Spectrum before plugging anything into either of the ports Failing to do this is unlikely to cause damage but could result in the computer crashing SENDING INFORMATION VIA THE INTERFACES Assuming that you have a printer connected to the Wafadrive by means of a suitable lead it should now be possible to print out programs and data Spectrum programs are tokenised in order to maximise the use of memory This means that all the commands LIST PRINT NEW etc are represented by a single code number as described in appendix A of the Spectrum BASIC Programming Manual When using a printer to produce program listings the tokens must be expanded into their full form The commands LIST and PRINT perform this function and can be used directly Associated with the RS232 and Centronics ports are two new channels R and C respectively Before using the RS232 interface however we must first set the Baud rate using the FORMAT command Here are two programs which produce listings on prin
17. 8K wafers Entrepo stringy floppy cartridges 16K 64K and 128K formatted Infinite loop 1 16 width Specially developed backing and lubrication 5000 passes min 67 x 45 x 6 mm By removable tab Automatic sliding cover prevents damage To computer via ribbon cable and standard Spectrum expansion connector Connections passed on at rear of Wafadrive enabling connection of Sinclair printer etc 9V nominal derived from computer RS232 INTERFACE Implementation Five wire RXD TXD RTS CTS and GND Baud rates Software selectable 110 150 300 600 1200 2400 4800 9600 amp 19200 CENTRONICS INTERFACE Implementation Eleven wire DATA 0 7 BUSY STROBE and GND OPERATING SYSTEM Size 8K ROM paged automatically Reserved RAM 2292 bytes with no files opened Files supported Number of files Program machine code or data files 32 maximum 16 using 16Kwafers ROTRONICS reserve the right to alter the above specification at any time without prior notice 41 INDEX Rotronics Wafadrive Manual doc In this Index entries referring to the normal Spectrum BASIC commands eg NEW also relate to their Extended BASIC counterparts eg NEW NEW A Access time Address bus Attributes Auto run B Baud rate Bootstrap BORDER BREAK Buffer BUSY BYT Byte C Capacity Carriage return CAT Catalogue C Centronics channel Centronics Channel CHR CLEAR CLOSE closing channels CLS
18. AD loading LLIST LPRINT Rotronics Wafadrive Manual doc 32 39 14 21 24 25 41 43 51 52 13 17 20 22 23 24 29 31 32 33 47 48 49 53 9 42 36 9 42 48 41 60 19 20 21 23 31 12 13 14 16 21 38 41 43 47 48 52 54 58 61 48 48 38 7 59 13 14 39 48 59 41 43 7 9 10 16 52 57 10 51 28 33 39 48 52 28 32 33 39 48 49 52 41 60 35 60 27 30 54 8 11 12 61 7 36 37 38 222333 28 32 38 49 52 20 23 24 43 49 51 52 53 54 28 32 38 28 38 43 M Machine code Memory map MERGE merging Modem Motor MOVE N NEW O OPEN opening channels Operating system P Packaging PAPER Parallel Parity PAUSE P printer channel PEEK Pointer POKE Port Predictive access PRINT Printer Protection PRG R RAM Read file REM Repair Report ROM RS232 RTS RUN RXD Rotronics Wafadrive Manual doc 23 24 41 49 52 53 54 57 60 57 21 22 24 41 43 48 49 52 35 39 8 11 59 60 24 25 34 52 see also Copying 9 10 20 21 38 52 29 30 31 32 33 47 48 49 51 52 53 59 9 10 27 42 44 52 62 8 10 51 see Centronics 36 28 27 29 30 54 17 55 41 17 55 38 54 57 59 60 41 28 32 38 49 53 27 28 30 35 36 38 61 21 22 41 48 51 19 58 see also File extension 9 10 25 42 43 52 58 62 49 57 see Servicing see Error 29 49 62
19. BASIC commands made available by the Wafadrive Operating System The Extended BASIC commands do not come into operation until the system has been initialised Once initialised the Wafadrive Operating System reserves about 2K of the Spectrum s memory for its own use system variables read write buffer and the two drive directories The user has the option of retaining the computer s full RAM capacity if the Wafadrive is not required for use without having to disconnect the unit if the initialisation process is omitted the computer will behave normally The system is initialised simply by entering NEW This is the only Extended BASIC command that the Spectrum will respond to until the system has been initialised The Wafadrive title message will now be displayed and the system is ready for use NEW may be entered at any time It does not affect any BASIC program currently in memory However once the system has been initialised NEW has no effect and will cause a syntax error If at any time there is insufficient memory remaining to allow the Wafadrive system to operate you will be unable to enter the NEW command All the extra commands made available by the Wafadrive system are suffixed either with the asterisk or hash symbols USING NEW The NEW command has exactly the same effect on BASIC programs as before However NEW will also reset the Wafadrive system freeing the reserved RAM The system must be re initialised be
20. CODE code Connections CONTINUE Control character Copying CPU CTS Custom commands D DAT DATA data Data file Data line Default drive Directory Drive specifier 11 60 61 42 10 51 22 23 53 54 36 38 48 52 54 61 41 10 51 11 13 16 23 41 51 9 25 31 32 44 57 58 59 37 59 60 62 23 58 see also File extension 13 31 35 44 52 53 54 55 57 58 59 61 11 61 see ENTER 15 16 17 43 45 51 see CAT Directory 30 38 54 30 31 35 36 37 38 54 59 60 62 27 28 29 30 31 44 51 52 53 54 57 58 59 38 39 30 32 51 29 30 32 33 47 49 10 51 23 24 38 see also Machine code 7 36 37 61 16 see CHR 24 25 34 41 47 48 52 42 36 62 42 31 58 see also File extension 27 30 31 32 33 38 53 54 30 31 32 33 34 47 49 51 53 54 59 37 62 16 17 19 20 24 31 45 51 52 54 9 10 13 15 16 17 19 20 21 23 24 31 32 39 41 43 44 45 47 51 52 53 57 58 13 16 19 24 48 54 42 E ENTER ERASE erasing Error formatting Error report message Error syntax Expansion bus Extended BASIC EBASIC F Fast forward File extension FORMAT formatting G GO SUB GO TO Graphics Guarantee H Head read write Hexadecimal Hook code I IN Index Initialisation INK INKEY INPUT Interrupt J Joystick K K keyboard channel L LED Lead LINE LIST LO
21. E d filename start length run Saves machine code bytes from memory Error report if file already exists Option to auto run code upon loading when required 34 SAVE Rotronics Wafadrive Manual doc If used instead of SAVE above does not produce error report if file of same name already exists in wafer directory Any such file is automatically over written VERIFY d filename Verifies BASIC or machine code program on wafer against that stored in memory The following abbreviations are used above baudrate channel data d filename length line port run Start stream string variables wafername RS232 transmit receive data rate Can take the value 110 150 300 600 1200 2400 4800 9600 or 19200 Channel specifier string Valid ones are P K S and their lower case counterparts Collection of numbers and or strings Drive specifier string Takes the form A B or their lower case counterparts If none stated then default assumed Name of program or data file Up to 10 characters system forces uppercase Number of machine code bytes to be saved or loaded line number String specifying RS232 or Centronics port channels Valid ones are R C and their lower case counterparts Line number or address from which program execution is to auto run when loaded Address in memory from which saving or loading of machine code block is to commence Stream numb
22. E w 110 PRINT SIZE w 2 K SPARE w 3 K 120 PRINT FILES w 4 PRINT 130 FOR e 1 TO w 4 140 PRINT d e ss e K 150 NEXTe 160 STOP The subroutine could also form the basis of a program to search for a particular file name on a wafer 30 Rotronics Wafadrive Manual doc ERROR REPORTS With the Wafadrive connected to your Spectrum several new reports are added as listed below Some of the reports will not normally be encountered when operating in BASIC although special programs may use them The error code for each report is given in brackets although this is not displayed See also the Spectrum BASIC Programming Manual appendix B Directory full 22 The maximum number of files that can be held on the wafer 32 has been reached Directory locked 24 An attempt has been made to access the wafer whilst a data file remains opened to it Close all files before saving erasing etc Drive write protected 8 An attempt has been made to save erase or copy to a wafer which has had the write protect tab removed Faulty Wafer 15 Obtained after four attempts at loading a file have failed or if verification fails on a significant number of sectors during formatting File exists 18 An attempt has been made to save a program using a name which already appears in the wafer directory This error is suppressed if SAVE is used instead of SAVE File opened for write 16 Not normally encountered Fi
23. O SUB 9800 9700 IF CODE a 0 THEN RETURN 9710 LET d e a 9720 NEXT e 9730 RETURN 9800 REM Build entry 9810 GO SUB 9900 9820 LET c PEEK a 4 INT PEEK a 4 9830 IF c 0 THEN LET a a PRG 9840 IF c 1 THEN LET a a BYT 9850 IF c 2 THEN LET a a DAT 9860 LET a a 1 LET z PEEK a LET s e z 9870 FOR n 1 TO z 1 LET a a 1 NEXT n 9880 RETURN 9900 REM Build name 9910 LET a 9920 FOR n 1 TO 10 9930 LET a a CHR PEEK a LET a a 1 9940 NEXT n 9950 RETURN Enter this with variable a 24862 for directory A and a 25444 for directory B To ensure that the directories are valid for the wafers in the drives use CAT to boot up the wafers first However note that this command also alters the default drive On exit the string variable a contains the name of the wafer WAFER_NAME The array w contains information about the wafer as follows w 1 The overall capacity of the wafer WAFERSIZE w 2 Number of good sectors on the wafer GOOD_SECT w 3 Number of sectors left available FREE_SECT w 4 Number of files currently stored FILES The array 5 contains the sizes of the individual files and the array d their names 29 Rotronics Wafadrive Manual doc If the following lines are added the action of the above subroutine can be demonstrated 10 REM Display directory 20 LET a 24862 30 INPUT DRIVE A OR B LINE a 40 IF a B OR a b THEN LET a 25444 50 GO SUB 9600 100 PRINT WAFER NAM
24. Rotronics Wafadrive Manual doc Rotronics Wafadrive 2004 OCRed by Wilko Schr ter THE ROTRONICS WAFADRIVE User manual SPECTRUM VERSION 16 48K Sinclair Spectrum model No 2302 Written and prepared by Graham Booth B Eng WAFADRIVE is a trade mark of ROTRONICS LTD Santosh House Marlborough Trading Estate West Wycombe Road High Wycombe BUCKS HP11 2LB ENGLAND ROTRONICS LTD A division of Rovo Financial Corporation Ltd Santosh House Marlborough Trading Estate West Wycombe Road High Wycombe Bucks HP11 2LB CONTENTS Introduction Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Rotronics Wafadrive Manual doc Unpacking and connecting Using the Wafadrive Initialising the system Using NEW Clearing BASIC programs Clearing the screen The wafers Preparing and naming wafers Protecting against accidental erasure Maintenance The Directory Displaying the Directory Setting the Default Drive Storing and retrieving programs Saving Verifying Loading Erasing Merging Saving using an existing file name Auto run programs Saving and loading machine code Copying programs Modifying existing programs Streams Stream handling on the unexpanded Spectrum Stream handling with the Wafadrive Storing and retrieving data Creating a Wafadrive data file Writing data to a Wafadrive file Reading data from a Wafadrive file Cop
25. This should lie between 0 and 255 Variable x is a dummy variable and returns no useful value It may seem strange to use the IN command to output something this is a quirk of the Wafadrive hardware and is done to prevent clashes with other T O devices The single bit input port BUSY can be read by performing LET x IN 2 However the port status is represented by the inverse of bit 5 of the returned value To determine the true status we have to mask off the other 7 bits and invert the result This is very simple in machine code and most dialects of BASIC but not so straightforward in Spectrum BASIC This program will do the job though 10 REM Read BUSY line 20 LET x IN 2 30 LET x INT x 32 40 LET x NOT x 2 INT x 2 50 PRINT x Normally this program will yield the result 1 since the BUSY line is internally pulled high via a 1K resistor Shorting the BUSY line to ground will give the result 0 The above technique can be used to read a joystick connected to the Centronics port via an adaptor which is available separately Details of how to scan a joystick are included with the adaptor The additional Centronics interface output line STROBE may also come in useful To write a value 1 or 0 to this line in BASIC use LET x IN 10 8192 NOT s Where s is the value to be written to the port and can be either 0 or 1 Variable x is again a dummy variable and returns no useful result When first switched on the STROBE l
26. a is anything which can be put in a DATA statement numbers letters symbols plus variables as distinct from programs which operate upon data At each end of a stream is a channel which is one of the computer system s input output devices In the basic Spectrum the channels are channel K or k the keyboard input output channel S or s the screen output channel P or p the Sinclair printer output The tape recorder interface is also an I O device but does not have any channels associated with it since data is handled in a different manner on tape There are sixteen available streams on the Spectrum numbered O to 15 Four of these are automatically linked to channels when the computer is powered up for use by the Spectrum operating system These are stream 0 input and output from keyboard stream 1 input and output from keyboard stream 2 output to screen stream 3 output to printer Streams 0 and 1 require a little further explanation Although there is physically only one keyboard device which can only input data logically on the Spectrum there is another keyboard device which is capable of outputting data from the computer This is the bottom part of the screen which as you will know is distinct from the main part of the screen That is why channel K is specified as an input output channel above Little is said about stream handling in the BASIC Programming Manual supplied with the computer but
27. alled a buffer The contents of the buffer are only transferred to the wafer when it becomes full or when the file is closed When an existing file is opened a buffer is again reserved in memory The first sector is read from the file and stored in the buffer ready for reading If when a data file is opened there is insufficient spare memory for the buffer to be created an Out of memory error report will be obtained WRITING DATA TO A WAFADRIVE FILE Data is written to the opened data file buffer using the PRINT command as with any other stream For example PRINT 4 HELLO a 32 writes the three pieces of data to stream 4 The individual elements should be separated by carriage return ENTER markers This can be achieved either by using the apostrophe as a separator or by using separate PRINT statements If semi colons or commas are used instead the data will be written but the INPUT statement will not be able to read it back again properly Remember that the data will not be stored on the wafer or the directory updated until the file has been properly closed Nor will the system allow a wafer to be accessed if any files opened to it have been left unclosed attempting to do so results in a Directory locked report Unclosed files are invariably unreadable A data file is closed simply by closing its associated stream For example CLOSE 4 closes stream 4and the corresponding data file The data will then be stored on the wa
28. ch access the drives operate FORMAT There are four stages to the process of formatting a wafer Firstly the tape is fast wound to reach the index Secondly the tape is fully wound at normal speed and the length number of sectors is determined Thirdly the individual sector headers and dummy data are written to the tape Finally the sector information is verified and the directory created Any sectors which fail the verification process are indicated in the directory as being unusable CAT If there is already a directory in RAM for the specified drive the system first makes a check to determine whether it is valid for the wafer currently in the drive This is done by reading the next sector on the tape Each sector header contains the wafer name given by the user during formatting the wafer name is checked against that appearing in the RAM directory if the two match then the system knows that the RAM directory is valid and can be displayed on screen If the two do not match then the directory must first be loaded from the wafer This method saves a great deal of time if the wafer has previously been accessed the directory will appear on screen in about a second SAVE When saving the directory is first validated Information in the directory is then used to determine whether or not a file of the same name already exists whether there is enough room on the wafer to store the program and free sectors available for storage The program
29. d quickly and efficiently This greatly increases the usefulness of your computer particularly if you have a printer and add on keyboard unit Readers of this manual should be familiar with the use of BASIC on the Spectrum If you have purchased a Wafadrive at the same time as your Spectrum first read the booklets supplied with the computer Rotronics Wafadrive Manual doc UNPACKING AND CONNECTING Upon opening the Wafadrive carton you should find the following items 1 The Wafadrive unit itself with integral connecting lead 2 A blank unformatted wafer 3 The Word Processor wafer 4 This manual The power lead must be disconnected from the computer before connecting the Wafadrive Failing to do this can result in damage being caused to the Wafadrive or your computer To connect the Wafadrive simply push the connector into the Spectrum rear expansion port ensuring that the locating key and slot are lined up first Never force the connector into position When not required the Wafadrive may be disconnected from the computer However it is recommended that this is done as infrequently as possible to minimise strain and wear of the connectors The Wafadrive does not affect the normal operation of the Spectrum unless it has been initialised When disconnecting always grip the connector assembly Never remove the connector by pulling on the ribbon cable Any additional peripherals may now be connected via the slot at the
30. directory of the wafer is displayed enabling wafers to be easily identified It is very important that you give each of your wafers a unique name If you do not you run the risk of confusing not only yourself but the operating system also with potentially disastrous results To format a wafer first insert it into either of the drives say drive A the left hand one Ensure that it is pushed completely home It is also advisable to ensure that there is no wafer in the other drive Now type in FORMAT a xyz 001 where xyz 001 represents your initials and a wafer number a different number for each of your wafers You don t have to name your wafers in this manner but it is advisable to be systematic and this is a good method The a section of the name string is the drive specifier This can only be either a or b upper or lower case according to which drive is being used Often the drive specifier can be omitted see chapter 4 The maximum total length of the wafer name is ten characters not including the drive specifier During formatting the tape length is measured to determine the capacity of the wafer The individual sectors on the tape are then created and verified and finally the directory is written Whilst this process is taking place the border will flash and status information is displayed on the screen The wafer capacity is measured in sectors with each sector corresponding to 1K bytes of storage One
31. e read write and channel buffers starting at address 24862 Each directory appears in memory as follows ITEM BYTES COMMENTS WAFERNAME 10 Name given to wafer when formatted ID_BYTES 2 Not normally used set to spaces DIR_ATTR 11 Not normally used set to spaces WAFERSIZE 1 Capacity of wafer sectors GOOD_SECT 1 Number of useable sectors FREE_SECT 1 Number of sectors yet unused FILES 1 Number of files on wafer DIR_SECT 1 Directory sector number SAM 20 Sector allocation bit map FILENAME_ 1 10 Name of first file FILETYPE_1 1 Indicates PRG DAT or BYT FILESIZE_1 1 Size of file sectors SECTORS_1 Varies Sector numbers occupied by file files 2 to 31 FILENAME_32 10 Name of last file FILETYPE _32 1 Indicates PRG DAT or BYT FILESIZE_32 1 Size of file sectors SECTORS _32 Varies Sector numbers occupied by file One byte for each sector occupied by the file Total number of bytes therefore given by contents of FILESIZE A BASIC program which reads the directory is given in chapter 9 THE READ WRITE BUFFERS There are actually four buffers created by the Wafadrive system in RAM The main read write buffer is approximately 1K bytes in size and is permanently located between the system variables and directory areas It is used by the system to hold sections of programs as they are read from or written to the wafers In addition there are three channel read write buffers The largest of these channel buffer
32. er lying between 0 and 15 Any chosen string of characters List of variable names representing numeric or string data Unique name given to wafers during formatting May be up to 10 characters upper or lower case 35 Rotronics Wafadrive Manual doc EXTENDED SYSTEMS VARIABLES Several new systems variables are added by the Wafadrive These occupy 102 bytes above the original Spectrum system variables starting at address 23734 Some of these can be usefully peeked and poked although it is very easy to crash the system if this is done inadvisedly Bytes Address Name Comments 1 23734 INITFG Initialisation flag 2 23735 SYNVCT Vector for syntax checking routines 2 23737 ERRVCT Vector for error handling 2 23739 STRVCT Vector for string printing 11 23741 ROMPAG Machine code paging routine 2 23752 BAUDRT Used for calculating Baud rate 1 23754 CHFLGA Channel opened flag for drive A 1 23755 CHFLGB Channel opened flag for drive B 1 23756 TMPFLG Temporary channel flags 1 23757 LOADNG Program load flag 1 23758 RTYCNT Retry count for sector read 1 23759 TMPDTO Temporary data storage byte 1 23760 TMPDT1 Temporary data storage byte 2 23761 XCHADD Initial text pointer 2 23763 CHADHL Sector allocation address 1 23765 ERRFLG Error flag used during formatting 1 23766 REPORT Current control port status 1 23767 LOGDRV Current logged drive O A 1 B 1 23768 DRIVNR Drive number 1 23769 SECTRA Sect
33. fer and the directory updated The global command CLEAR may also be used Program listings may also be written to data files using LIST or LLIST 20 Rotronics Wafadrive Manual doc READING DATA FROM A WAFADRIVE FILE To read items of data from an opened file use INPUT For example INPUT 4 a b 3n fetches the first three items of data from the file previously opened to stream 4 and assigns them to variables The variable types ie string or numeric must correspond to the data stored As you will know the INPUT statement is also able to output to the bottom part of the screen Commas and apostrophes have an effect on output print format and therefore give rise to Writing to a read file error report This is why semi colons should be used to separate the variable names they have a null effect on print format The INPUT statement expects to see ENTER characters after every item of data just as it expects the ENTER key to be pressed after data has been typed in at the keyboard This is why apostrophes are used as data separators when writing to a data file they have the same effect as ENTER An alternative way of reading data from a file is to use INKEY This returns the next character in the file For example 10 REM filetest 20 OPEN 4 a testfile 30 LETa 40 FOR n 32 TO 143 50 LET a a CHR n 60 NEXT n 70 PRINT 4 a 80 CLOSE 4 100 OPEN 4 a testfile 110 FOR n 1 TO 112 120 PRINT INKEY
34. fore it can be used again CLEARING BASIC PROGRAMS The NEW command clears out any BASIC program without resetting the Wafadrive Operating System Although the initialisation process is virtually instant the use of NEW instead of NEW means that the directories do not have to be re fetched from the wafers more of this in chapter 4 Note that NEW or NEW cannot be incorporated into BASIC programs they can only be executed directly from the keyboard CLEARING THE SCREEN The Wafadrive adds an additional command which although not directly related to the operation of the drives is nevertheless very useful It is CLS which performs the normal CLS function but in addition also clears the screen attributes resetting them to their initial values of PAPER 7 BORDER 7 INK 0 etc Text will therefore revert to black on white Rotronics Wafadrive Manual doc THE WAFERS Wafers are available in three sizes having nominal capacities of 16K 64K and 128K after formatting The average access time ie the length of time you have to wait whilst the file you want is found on the wafer increases in proportion to the capacity The 16K wafer holds a reasonable amount of data and gives very rapid access The larger capacity wafers give more cost effective storage but on average you will have to wait slightly longer before files are located on the wafer The user can choose the size of wafer to suit particular applications The s
35. he wafer in the default drive to be loaded in 12 Rotronics Wafadrive Manual doc ERASING Assuming that the program colours is still in the computer save it again but this time give it the name fest You should now have two versions of the program on the wafer To erase the unwanted one you have just saved enter ERASE a test There is a wildcard facility that operates in conjunction with the ERASE command This is best illustrated by an example The statement ERASE a te causes all files begining with TE to be erased from the wafer in drive A The asterisk takes the place of the missing letters The statement ERASE a causes all files on the wafer to be erased This feature can be very useful it is a lot faster than re formatting but should be used with caution for obvious reasons To avoid confusion do not use file names ending in asterisks Note that the asterisk cannot be put at the begining of the file name ERASE st Does not erase all the files ending in ST Commercially produced software is sometimes protected in a special manner Protected files indicated by a suffix after the file extension in the directory cannot be removed using the ERASE command These files can only be removed by re formatting the wafer MERGING The procedure for merging BASIC programs is straightforward Enter NEW then type in 100 REM colours IT 110 CLS 120 FOR n 1 TO 704 130 PRINT PAPER 8 RND INK 8
36. if you PEEK this location you can determine which drive is the current default Be careful to adhere to the above values careless POKEs can be the equivalent of putting a spanner in the works 10 Rotronics Wafadrive Manual doc STORING AND RETRIEVING PROGRAMS SAVING The procedure for saving programs on Wafer is very similar to that when using cassettes Type a short program into your Spectrum if you want an example try this 10 REM colours 20 FOR n 1 TO 704 30 PRINT INK 8 RND CHR 143 40 NEXT n To save this assuming you have a wafer in drive A enter SAVE a colours The program is first saved then the directory of the wafer is updated indicated by the border flashing Since A is usually the default drive we could have abbreviated the previous statement to SAVE colours From now on commands will include the drive specifier to illustrate the syntax but remember that it can be omitted when referring to the default drive As with names of programs stored on cassette Wafadrive file names can be up to ten characters long this does not include the drive specifier character and colon when used Unlike cassette program names however Wafadrive file names are always converted to upper case so as to avoid ambiguity File names can take the form of valid string variables as well as literal strings Now that the program is stored examine the directory again You will see that the name now appears in upper case
37. ine is at logic 1 39 Rotronics Wafadrive Manual doc It is possible to control the Wafadrive motors directly The ability to fast wind the wafers under program control can greatly reduce the access time under certain circumstances This would normally be done by a machine code program which intercepted the interrupt handling routine of the Spectrum so that the fast wind period could be timed transparently to the operation of the main program After winding the tape the sector pointers in the system variables area must be updated as appropriate The implementation of such a system is fairly involved and beyond the scope of this introductory manual 40 Rotronics Wafadrive Manual doc SPECIFICATION PHYSICAL Size 230 mm wide x 110 mm deep x 80 mm high Weight 900 g Cabinet Injection moulded textured ABS Colour Black with colour graphics Indicators Red LEDs two drive active one power DRIVES Type Dual BSR stringy floppy Capacity Min 128K formatted using 50 wafers Tape format Data format Tape speed Data integrity Reliability Transfer rate Access time WAFERS Type Capacity Tape Life Size Write protection Tape protection ELECTRICAL Connections Power source Single track 1K sectors FM encoded The 10 sec read write 15 sec search 1 in 10 8 bit error rate 5000 hours MTBF 18K Baud 2K Bytes sec approx Worst case 6 5 secs 16K wafers 45 secs 12
38. ing original information connections listings etc which may be of assistance to other Wafadrive owners in relation to the operation of the RS232 interface 26 Rotronics Wafadrive Manual doc HOW THE WAFADRIVE WORKS This chapter is aimed at those people who wish to explore the workings and facilities of the Wafadrive further It is assumed that the reader is familiar with the basic operation of the Spectrum computer system SYSTEM OPERATION The drives run at two speeds depending upon whether they are searching for a file or reading writing from to it The system works out how long to wind the tape at fast forward before slowing down ready to access a file or the directory It can do this because it maintains a pointer in the extended systems variables which indicates the last sector accessed The wafer directory contains all other information required to perform the calculation Incidentally if you are clever with machine code it is possible to implement a predictive access technique whereby the tape is positioned such that the next required block can be accessed with virtually zero delay If done under interrupt control this can be performed transparently to the operation of any program being executed In the wafers the tape loop is completed by a conductive splice a section of metallic leader tape which is detected by the Wafadrive hardware and acts as an index marker The directory is stored in the first good sector after the i
39. is written to the tape sector by sector then the directory is updated LOAD Again the directory is first validated After checking that the program exists and the sectors it occupies the program is loaded in sector by sector The directory does not need to be modified afterwards so loading is usually quicker than saving ERASE The directory is first validated The entry relating to the specified program s is then deleted from the wafer directory VERIFY This is very much like LOAD except that the specified program on the wafer is checked against that stored in memory MERGE Again very similar to LOAD except that the program on the wafer is combined with that in memory 28 Rotronics Wafadrive Manual doc READING THE DIRECTORY FROM BASIC Two directories are maintained in RAM by the Wafadrive Operating System one for each drive These hold all important information about the wafers the drives and the files stored on them The directories each occupy 582 bytes and are located between the read write buffer and the channel information area starting at address 23734 Reference should be made to appendix 4 for more complete information A subroutine to read the RAM directories from BASIC could take the form 9600 REM Directory read routine 9610 DIM w 4 DIM s 32 DIM d 32 14 9620 GO SUB 9900 9630 LET w a LET a a 13 9640 FOR n 1 TO 4 LET w n PEEK a LET a a 1 NEXT n 9650 LET a a 21 9660 FOR e 1TO 32 9670 G
40. ith a file opened for writing only Stream already opened 5 The stream specified in an OPEN command is already opened Streams must be closed before they can be re assigned to other channels Verification failed 13 The program in memory does not match that specified in the VERIFY command Wafer full 9 There is insufficient space remaining on the wafer to allow the specified file to be stored Wafer not inserted 10 There is no wafer present in the specified drive Writing to a read file 6 PRINT LIST or INPUT with invalid separator has been used in conjunction with a file opened for reading only Wrong file type 14 Occurs when an attempt is made to load a data file merge a data or machine code file open to a program file etc 32 Rotronics Wafadrive Manual doc COMMAND SUMMARY The commands relevant to Wafadrive operation are summarised below in alphabetical order BREAK Direct command may be used to abort execution of BASIC at any time except when loading a protected program During some Wafadrive operations it may be necessary to hold the BREAK key down for a second or two until the operation is halted CAT d Display the directory of the water in the specified drive CAT d Loads in the directory of the specified drive without displaying it on screen Also sets the default drive to that specified CLEAR Closes all previously opened streams setting streams 0 3 to their initial allocations
41. ive A is made the default We can therefore simply enter CAT to display the directory of drive A This applies to all Wafadrive commands that require a drive specifier We could have used it when we formatted the wafer in the last chapter although it is a good discipline to be specific when formatting to reduce the possibility of costly mistakes The default drive feature simplifies the use of the Wafadrive and saves typing You will find this feature most helpful if you use A as the general working drive with B as the secondary drive Rotronics Wafadrive Manual doc SETTING THE DEFAULT DRIVE Should you ever want to you can alter the default drive yourself using a variation of the CAT command For example to change it to B enter CAT b If there is no wafer in the specified drive you will get an error message Apart from setting the default CAT also loads in the directory of the wafer without displaying it on the screen thus ensuring that the version of the directory in RAM is valid for the wafer in the drive This could be useful if we wanted to read the directory from BASIC for example see chapter 9 Entering CAT just causes the directory of the current drive to be loaded without displaying it Another way to set the default without loading in the directory is to POKE one of the extended system variables POKE 23767 0 sets the default to drive A POKE 23767 1 sets the default to drive B Similarly
42. l printer commands LPRINT and LLIST could have been omitted from Spectrum BASIC without causing any great inconvenience In fact most other versions of BASIC do not provide them Streams can be assigned to channels using the OPEN command Streams 4 15 cannot actually be used without first being opened whereas 0 3 are opened automatically by the computer when switched on OPEN may be used to re direct streams 10 LET a The ROTRONICS Wafadrive 20 OPEN 2 p 30 PRINT a Line 20 determines that subsequent output via stream 2 which is normally assigned to channel S the screen should go to channel P the printer A single line similar to this at the begining of a program will cause all screen data to be sent to the printer The opposite effect is also possible of course A stream can be closed to disconnect it from the channel it has been assigned to Closing any of the streams 0 3 has the effect of re assigning them all to their original channels and is accomplished thus 10 LET a The ROTRONICS Wafadrive 20 OPEN 2 p 30 PRINT a 40 CLOSE 2 50 PRINT a Additional streams can be opened for use if required This can be demonstrated simply by altering the stream number in the program above from 2 to any number between 4 and 15 inclusive Attempting to send or receive information to or from an unopened stream will result in an error report A bug in the Spectrum ROM can cause some problems when trying to cl
43. le name missing 4 Not normally encountered File not found 11 The specified file does not appear in the wafer directory File read only 23 An attempt has been made to copy a protected file File write protected 21 You have tried to erase or overwrite a protected file Invalid Baud rate 17 The baud rate specified in the RS232 FORMAT statement is not one of the nine available Invalid drive 3 A drive has not been specified as either A a B or b Also occurs if trying to copy multiple files onto the same wafer 31 Rotronics Wafadrive Manual doc Invalid hook code 19 Not normally encountered Invalid name 2 The file name specified is invalid more than ten characters for example Also occurs if attempting a copy a single file onto the same wafer without renaming Invalid stream number 1 The stream number specified is not within the allowed range 0 to 15 Merging error 12 The MERGE command has not been executed successfully Nonsense in BASIC 0 The contents of a string do not form a valid Extended BASIC expression Out of range 20 The argument of a function is outside the permitted range Program finished 255 Occurs if a line number is specified in a RUN GO TO or GO SUB statement which exceeds the highest line number in the program Also obtained if RUN is entered when no program is in memory Reading from a write file 7 INPUT or INKEY has been used in conjunction w
44. maller wafers are recommended for program development where programs are generally small and fast access is important Finished programs back up copies and data can be archived onto larger wafers freeing the smaller ones for further use The tape inside the wafers is protected by an integral sliding cover which is automatically moved across to expose the tape when the wafer is inserted into the drive Touching the tape can damage it avoid doing so If It is possible to remove a wafer from a drive whilst the drive motor is running signified by the drive active LED being lit There is virtually no possibility of damage but doing this habitually could have a detrimental effect on the life of the wafers Removing wafers in this way should not be necessary unless the system crashes whilst the motor is running only likely if you are experimenting with machine code Usually the BREAK key can be used to stop the motor before a wafer is removed Care should be taken to ensure that wafers are withdrawn from the drives when the power is applied or removed especially if either of the drives is active The system has been designed to cope with this to an extent and you would be very unlucky to lose data in the event of a power cut for instance However as a general rule AVOID REMOVING WAFERS WHILST THE DRIVE ACTIVE LEDS ARE ILLUMINATED ALWAVS REMOVE WAFERS BEFORE SWITCHING THE POWER TO THE COMPUTER ON OR OFF You will soon learn tha
45. n wafer should be compatible with joysticks connected in this manner For the electronics enthusiast the parallel interface has the incidental benefit of acting as an eight bit output port enabling communication with other non standard peripherals See appendix 4 for further information THE RS232 INTERFACE The RS232 interface is bidirectional enabling data to be both transmitted and received It is referred to as a serial interface because data is transmitted a bit at a time along a single wire The computer and peripheral must perform the conversion between serial and parallel at either end deal with the two way data flow and provide relatively large signals It is therefore somewhat more difficult and hence usually more expensive to implement than the Centronics interface Unfortunately the RS232 specification is a loose one There are many variations and options to confuse the novice and expert alike If you are considering buying a printer one offering a Centronics interface will usually be the most straightforward to connect and get operational The RS232 interface on the Wafadrive takes the following format Lines RXD Received Data input TXD Transmitted Data output RTS Ready to Send input CTS Clear to Send output Parity check None Number of bits Eight Stop bits One Baud rate 110 150 300 600 1200 2400 4800 9600 or 19200 software selectable Default rate 1200 Baud Baud rate error 3 max
46. ndex When a wafer is first accessed the tape is fast wound until the index is reached then slowed ready to read the directory The directory sector has the facility to store a bootstrap routine If implemented this routine will be executed as soon as the wafer directory is accessed overriding control of the system This is done principally to allow software to be made secure and for obvious reasons details of this aspect of Wafadrive operation are not released to the general public Files can be tagged as protected in the directory Protected files cannot be copied or merged nor can they be erased without re formatting the wafer The BREAK key cannot be used to abort loading of a protected program Again this is an aid to software security and details are not made generally available OPERATION OF THE EXTENDED BASIC COMMANDS The Extended BASIC EBASIC commands are provided by the Wafadrive Operating System WOS which resides in 8K of ROM This ROM is located at address 0000 of the Spectrum s Z80 memory map sharing this space with the lower 8K of the existing Spectrum 16K ROM Obviously it is not possible for the two ROMs to co reside in the same address space without disrupting each other s control over the CPU Whenever the Wafadrive ROM comes into operation therefore the Spectrum ROM must be paged out and vice versa This is performed by hardware in the Wafadrive which monitors the address bus Whenever the ROM routine at location
47. ode use PRINT 4 CHR 27 CHR 91 CHR 49 CHR 109 Hexadecimal conversions are given in appendix A of the Spectrum BASIC Programming Manual The appropriate codes for your printer will be found in the manual supplied with it The directory may be printed out using a simple routine like this 10 OPEN 4 c 20 PRINT 4 30 CAT a 40 CLOSE 4 RECEIVING INFORMATION VIA THE RS232 INTERFACE Information can also be received via the RS232 interface from peripherals such as terminals modems or other computers BASIC is too slow and restricted for efficient communication but it is possible to obtain some useful results INPUT and INKEY will both work but the latter is the most commonly used because it does not require carriage return ENTER characters to be received before the data is accepted If you have a terminal or other RS232 device which is capable of transmitting this program will display anything sent 10 FORMAT r 2400 or to suit 20 OPEN 4 r 30 PRINT INKEYS 4 40 GOTO 30 FURTHER INFORMATION ROTRONICS as a service to Wafadrive users will make available an information sheet giving details of RS232 connections found to work with various popular printers This will be free upon request and can be obtained by sending an s a e with a first class stamp to the address given at the beginning of this manual ROTRONICS at their discretion will supply a free blank wafer cartridge to anyone supply
48. ogramming Manual For example to save the screen after the program colours has finished use SAVE a display 16384 6912 Note that CODE is omitted The Wafadrive operating system recognises that it is machine code by the presence of the start and length parameters treating it accordingly Machine code files appear in the directory with a BYT suffix In this particular case SCREENS can also be used SAVE a display SCREEN A useful feature of the Wafadrive is the ability to save machine code such that it will auto run when loaded back This is done simply by specifying a third run parameter the address from which execution will start when loading has been completed The general form of the Wafadrive SAVE command is therefore SAVE d filename start length run SAVE can be used in the normal manner if it is required that any existing file of the same name should be overwritten The syntax used when loading machine code is simply LOAD d filename start Note again that CODE is omitted If it is required that the code be relocated upon loading the start parameter should specify the address at which it should be located If the code is to be loaded back to the same address it was originally saved from start can be omitted To load back the previous display simply use LOAD a display VERIFY operates in a similar fashion to LOAD and machine code files can be deleted using the ERASE command as with any other file
49. or under head drive A 1 23770 SECTRB Sector under head drive B 1 23771 SLFAST Fast forward data for I O control 1 23712 SLREAD Read control port 1 23773 SLWRIT Write control lines for current drive 1 23774 SLINDX Index mask 2 23775 DIRPNT Points to current RAM directory 1 237171 RDYDYA Ready flag directory A 1 23778 RDYDYB Ready flag directory B 2 237719 TEMPWO Temporary word storage 2 23781 TEMPW1 Temporary word storage for SAVE LOAD 2 23783 TEMPW2 Temporary word storage RUN address etc 12 23785 SCRATO Used when scanning names 16 23797 SCRAT1 Used when reading sector header 12 23813 SCRATM Destination file name in MOVE statement 11 23825 BUFFER Supplementary read write butter area 36 Rotronics Wafadrive Manual doc MEMORY MAP AND PORT ADDRESSES THE MEMORY MAP When the Wafadrive is initialised the Spectrum memory map is altered as follows 23734 23836 24862 25444 26026 CHANS PROG SYSTEM VARIABLES EXTENDED SYSTEM VARIABLES READ WRITE BUFFER DIRECTORY A DIRECTORY B CHANNEL INFORMATION CHANNEL BUFFERS BASIC PROGRAM AREA 102 bytes 1026 bytes 582 bytes 582 bytes Note that the BASIC program will be moved as channels are opened and closed Any machine code programs stored in REM statements should take account of this 37 Rotronics Wafadrive Manual doc THE DIRECTORIES The directories each occupy 582 bytes and are located between th
50. ose streams in the range 4 15 If an attempt is made to close one of these streams when it is not open strange things can happen If you are lucky an irrelevant random error report is given If you are not the computer crashes and your program is lost The advice here is to be careful 18 Rotronics Wafadrive Manual doc STREAM HANDLING WITH THE WAFADRIVE The Wafadrive unit adds two new channels to the Spectrum These are channel R or r the RS232 serial port input output channel C or c the Centronics parallel port output The use of the serial and parallel ports is covered in chapter 8 In addition the user can also set up data file channels files stored on wafer which can be read to or written from These are used to store data as distinct from programs and machine code and are discussed in the next chapter Three new commands are also made available OPEN acts in the same way as OPEN but is used when opening streams to the new Wafadrive channels described above Note that OPEN will not recognise these new channels Also if K S P or their lower case counterparts are used in an OPEN statement the Wafadrive system will open data file channels with these names instead of opening streams to the keyboard screen or printer CLOSE is used to dose any stream and should be used instead of CLOSE whenever the Wafadrive is in use The problem with the original Spectrum CLOSE command does not occu
51. r using CLOSE CLEAR has the effect of closing all currently opened streams and data files Streams 0 3 are reset to their initial allocations 19 Rotronics Wafadrive Manual doc STORING AND RETRIEVING DATA CREATING A WAFADRIVE DATA FILE We have seen how programs can be saved and loaded to and from the Wafadrive and the way in which streams are used in the Spectrum to handle data Now we shall look at the way in which special files are created on wafer to enable data to be both stored and retrieved A stream can be opened and assigned to a Wafadrive data file thus OPEN 4 a testfile The rules governing data file names are the same as for program names ie ten characters maximum forced to upper case The only restriction is that files cannot take the names R or C These names are reserved for the RS232 and Centronics channels After opening to a Wafadrive file the directory of the wafer in the specified or default drive is checked to determine whether or not the file exists If no file of the same name is found a new one is opened and designated an output write file If the file does exist it is opened as an input read file Attempting to open a non data file ie one not carrying the DAT file extension in the directory will result in a Wrong file type error The action of opening a new file does not mean that it will immediately be created on the wafer Initially an area of memory about 1K bytes is reserved c
52. rear of the unit Ensure that the peripherals you intend using are compatible with the Wafadrive The number of items that can be connected to the Spectrum at any one time is limited It is wise to keep the loading on the computer to a minimum to avoid unreliable operation or possible damage The power may now be reconnected to the Spectrum whereupon the screen will display the normal Sinclair copyright message The computer will behave exactly as normal since the Wafadrive system will not be effective until it is initialised see chapter 2 There are three indicator LEDs between the drive apertures The centre on is the power on indicator which will light up whenever power is applied to the computer The remaining two to the left and right are the drive active indicators These will illuminate whenever the drive motors are running Do not discard the Wafadrive packing materials If your unit is ever required to be serviced or repaired it should be returned in the original packaging All parts supplied with the Wafadrive should be included together with a clear description of the problem Rotronics Wafadrive Manual doc USING THE WAFADRIVE INITIALISING THE SYSTEM The many extra facilities that the Wafadrive adds to the Spectrum are provided by the Wafadrive Operating System WOS which is similar in many ways to the Disk Operating System DOS found in larger computers The extra facilities are accessed by means of the Extended BASIC E
53. se SAVE to overwrite a protected file will result in an error report AUTO RUN PROGRAMS BASIC programs may be made to auto run on loading by using LINE as with programs stored on tape If you still have the colours program in the computer enter SAVE a autocolour LINE 10 Examining the directory will show that the program autocolour appears with an asterisk after the file extension indicating its auto run status If you have followed the examples so far you will have two programs on the wafer in fact two versions of the same program Load in colours then re save it with the same name using SAVE This has the effect of making the autocolour program the first one to appear in the directory Now enter LOAD whereupon autocolour will load and auto run If problems are experienced with loading a file four attempts will be made before the system halts with a Faulty wafer error report As usual the BREAK key can be used to abort the loading process if required During loading of protected programs however the BREAK key is disabled If a protected program fails to load you should wait until the error report appears If you are really impatient you can pull out the wafer and start again but this is not recommended 14 Rotronics Wafadrive Manual doc SAVING AND LOADING MACHINE CODE The procedure for saving and loading machine code on the Wafadrive is similar to that used with cassettes see chapter 20 of the BASIC Pr
54. t your Wafadrive system is very reliable The wafers have been designed to sustain 5000 passes and with careful use are capable of achieving double this figure Despite this it should be remembered that the wafers do have a finite life and that accidents can happen It is strongly recommended that all important programs and data are backed up onto other wafers or possibly even cassettes Do not leave wafers in the drives when not in use Store them in a dry place where they will not be subject to extremes of temperature Keep wafers away from the TV set Spectrum power supply cassette recorder and any other equipment likely to be the source of strong magnetic fields Rotronics Wafadrive Manual doc PREPARING AND NAMING WAFERS Like disks but unlike cassettes blank wafers cannot be used straight away as supplied from the factory They must first be formatted using the FORMAT command Commercially duplicated wafers are formatted during the duplication process and can be used straight away The most important thing to remember about formatting is that any data and programs stored on the wafer will be erased Therefore be absolutely sure that nothing of value is stored on wafers before you attempt to format them Once formatted wafers will not normally require re formatting unless you want to wipe them clean for any reason The FORMAT command allows each wafer to be individually named This name appears on the screen when the
55. ters via the appropriate ports 10 REM CENTRONICS 30 OPEN 4 c 40 PRINT 4 The ROTRONICS Wafadrive 50 LIST 4 60 CLOSE 4 10 REM RS232 20 FORMAT r 2400 30 OPEN 4 r 40 PRINT 4 The ROTRONICS Wafadrive 50 LIST 4 60 CLOSE 4 These programs use streams in the normal manner so should be quite straightforward Line 20 above sets the RS232 port Baud rate to 2400 Substitute your own figure here as required As always be careful with the syntax of the FORMAT command When first switched on the Baud rate defaults to 1200 If your peripheral is set to operate at 1200 Baud there is no need to use the FORMAT statement Assigning stream 3 to the output ports causes LPRINT and LLIST to work with your printer instead of the normal Sinclair printer Peripherals will not interpret the graphics characters correctly when using PRINT LIST etc If the item to be printed contains graphics characters these will either be ignored or will cause strange effects One way round this is to refer to graphics characters using CHR To print out graphics characters correctly on a printer that is capable of reproducing graphics you will have to write or buy special software suitable for your particular printer 25 Rotronics Wafadrive Manual doc To send control characters to peripherals use the CHR function For example if your printer requires the sequence of hexadecimal codes 1B 5B 31 6D to switch it into extended typeface m
56. wafer is best left until you are ready for a coffee break MOVE works with program machine code and data files but will not allow copies of protected files to be made MODIFYING EXISTING PROGRAMS The vast majority of BASIC programs should function normally with the Wafadrive connected Simply convert the LOAD SAVE etc commands into the appropriate forms However there may be problems with programs that make extensive use of PEEK and POKE Without detailed knowledge of the program s operation these may be tricky to convert The fact that the Wafadrive reserves just over 2K of RAM could also prevent larger programs from working particularly with the 16K version of the Spectrum Commercially produced software in cassette form is invariably written in machine code and protected against copying in any way It is intentionally very difficult to break into such programs so there is little chance of you successfully transferring them onto wafer If you are really determined writing to the Software house concerned may produce some information which could be of use 16 Rotronics Wafadrive Manual doc STREAMS STREAM HANDLING ON THE UNEXPANDED SPECTRUM The Wafadrive operating system makes available commands which extend the stream handling capabilities of the Spectrum Streams can be used to some extent on the basic machine however without the Wafadrive being connected Streams are the routes along which data flows in the computer Dat
57. ying data files Centronics and RS232 interfaces The Centronics interface The RS232 interface Connecting peripherals Sending information via the interfaces Receiving information via the RS232 interface Further information How the Wafadrive works System operation Operation of the Extended BASIC commands Reading the directory from BASIC 11 15 19 27 31 35 41 Rotronics Wafadrive Manual doc Appendix 1 Error reports 47 Appendix 2 Command summary 51 Appendix 3 Extended system variables 55 Appendix 4 Memory map and port addresses 57 The memory map The directories The read write buffers Control ports Appendix 5 Specification 61 Index 63 INTRODUCTION The Wafadrive is a fast access storage system using special magnetic tape drives It enables programs and data to be loaded into your Spectrum much more quickly and conveniently than is possible using cassettes Furthermore file handling is easily performed since the Wafadrive locates files automatically without the operator having to position the tape The Wafadrive unit also incorporates two interfaces which enable the Spectrum to drive most printers that are Centronics or RS232 compatible This covers the vast majority of printers that are generally available A full specification Word Processor is supplied with the Wafadrive so you can start using your new system straight away The Word Processor allows documents and correspondence to be prepared and file
Download Pdf Manuals
Related Search