Ruud_at_baltissen.org
Date: 2006-05-27 21:54:45
Hallo allemaal,
I have my 1541LPT project working :) It hasn't been fully fool proof tested
but it works. I can format a 'disk', save and load a one-liner and read the
directory. And IMHO the rest should work as well as in fact I only altered
the parts that are involved with writing to or reading from the floppy-
disk.
Some technical information:
- one only needs to add a 6522 to the board and solder a 25 pin D-connector
to the 6522.
- I mentioned adding extra 2 KB of SRAM but you can forget that. At this
very moment I'm only using TWO bytes of that RAM and IMHO it shouldn't be
difficult to find a home for them in the first 2 KB.
- At this moment the extra ROM part is 778 bytes big. The original format
routine alone needs about 640 bytes and so, together with the unused 256
bytes at $C000, I could squeeze it in the original ROM. But that would mean
no extra commands at this moment like "changing disk".
- The PC runs a little Pascal program. At this moment it loads an hardcoded
D64 image. It is not much trouble to alter so it will use a parameter to
tell it what disk to use. There is a way to tell the 1541 that the PC has
'stopped' and started again. In this case the 1541 will reset as well.
Future:
- I first will optimize what I have at this moment.
- Add some extra commands like 'change disk'
- Maybe using G64
- Find out if I can find a place for all the routines inside the original
ROM
- Making a JiffyDOS version. FYI, the only part that my program affects is
the format routine.
--
___
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/ / |_/ Groetjes, Ruud
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\___| http://Ruud.C64.org
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