Re: 1541LPT
- From: Tomaz Kac <tomcat@xxxxxxx>
- Date: Fri, 02 Jun 2006 07:47:09 +0200
Great stuff there Ruud !
Something we have been waiting for. If only the software would run under Windows
;-) Already have to boot to DOS for 64HDD and 1541emu.
I know Ville Muikkula was working on something similar a few years back, might
of been a bit more complicated than this though (with RAM for images on the
actual drive) - maybe he could tell us more about that and what happend to it ?
:)
Anyway, I think this is a good way of going for an (almost) full emulation of
1541. Altough with todays super-fast PC's and USB ports, a simple communication
card for the USB2.0 would probably made a full blown 1541 emulator on the PC a
possibility. But that would require a lot of HW knowledge and a cycle-exact 1541
emulator running on a non-realtime OS. Probably not doable, but who knows... :)
Also one thing to consider is a plethora of CompactFlash, SD-Card, IDE, etc.
interfaces that are emerging for the C64, one would probably prefere having all
software on a small CF card and not having to boot up the PC to load some games
for the C64. But not everything is hacked to use kernal loaders, unfortunetly.
So your interface definetly has a place here. I will definetly hack apart one of
my 1541-II drives, possibly at the moment someone makes Windows software for
this ;-)
Best regards,
Tomaz
On 31 May 2006 23:41:24 -0700, Ruud.Baltissen@xxxxxx wrote:
Hallo allemaal,
I want to introduce 1541LPT. 1541LPT is a project where the PC will
replace the mechanical part of your 1541 drive. This involves some
changes of the hardware:
- a 6522 has to be added to the system
- the 6522 has to be connected to the LPT port of the PC in some way
- the routines transferring data to/from the real floppy disk have to
replaced by ones that transfer the data to/from the extra 6522
- the ROM(s) have to be replaced
1541LPT is not 100% compatible. Software manipulating the 6522, that
normally hanldes the data for the floppy, directly won't cooperate with
1541LPT. This is the case with the Final Cartridge-III and EXOS V3. But
the KCS Power Cartridge and JiffyDOS (!) seems to work fine.
The idea was to keep the 1541-ROM as original as possible by replacing
original instructions with JMPs or JSR's to the $8000-$BFFF range. This
meant that there was an additional hardware change needed as none of
the 1541 systems known to me support 32 KB EPROMs. So I decided to make
a small version by replacing complete parts of the original ROM by my
own ones: 1541LPTS. Unfortunately I'm not familiar enough with the
internals of JiffyDOS to decide what parts could be overwritten. So for
the JiffyDOS version of 1541LPT, 1541LPTJ, you need a 32 KB ROM.
Another problem is that JiffyDOS still is a commercial product ie. no
freeware so I cannot give you the binaries or sourcecodes. However, the
good news is that the instructions that have to be changed are exactly
the same as with the original version (at least the one I have). If I
counted correctly: 37 bytes that have to be replaced and another 13 for
changing the 73 message (not really needed).
Regarding the PC: at this moment the software runs on a 80486 80 MHz
under DOS 6.22 NL. It also runs fine in the real DOS mode of W98SE but
it won't run in a DOS-box in GUI mode.
Last remark: this is version 0.10 and so you'll find test code and
other ugly things in the sources. And I just realised that, although I
included the sources, I forgot to include the executable for the PC. I
hope to correct this this evening.
For more info and downloads: http://www.baltissen.org/htm/1541lpt.htm
Have fun!
Tomaz Kac |\ _,,,---,,_
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