This is an adapter for connecting the 1541 (or other IEC floppy disk drives) to the Userport of a CBM8032 etc. It is the reconstruction of a hardware, that fits to an old EPROM, that was found in a CBM8032. Most likely, it works with other BASIC 4.0 CBM/PET computers.
For communication with the disk drive, a special instruction set is required.
• each instruction starts with '!'
• there are a couple of floppy disk related instructions, that have an alternative representation in the EPROM
• a !q will deactivate/quite the software
• a !@ will display the status of the 1541
• a !@"command" will send a command to the 1541
• No device number (,8) is required for any of the instructions
• The instructions are mostly standard BASIC4 instructions and can be short-cut as usually
!load"progname": loads a program from 1541
!save"progname": saves a program to 1541
!verify"progname": verifies a program
!catalog: displays the driectory of the floppy disk in the 1541
!open#SA,"file name": it requires a # and after that it is a secondary address*
!print#,"text": prints a texts, also a secondary address after #*
!get#: *
!close#SA: closes a file, also a secondary address after #*
!input#SA: *
!cmd: *
The items marked with * require some further investigation. See the test documentation.
The software resides in a 2532 EPROM in UD11 and is started with SYS40960.
Find more in the project documentation and my website
Mike Naberezny did some further inverstigation of the EPROM binary/disassembly and has found out some interesting details. Check out his github repository.
The CB2 was improperly labled as CA2. This is fixed in the Gerbers v0a. This had no effect on the function of the circuit.