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Posted By
JamesC
on 2003-01-15
|  Atilla I wish you luck
but 1551s on Ebay Germany are not cheap.....
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Posted By
Gaia
on 2003-01-15
| Thanks
(SVS: I've got your email with the scans, thanks a bunch!)
That post on the cbm-hacker's list , while better than nothing, delivers not too much new information....  I'm trying now to get hold of a 1551 drive on E-bay Germany...
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Posted By
SVS
on 2003-01-14
 | --> Attila: Info about 1551 data tranfers,
and IRQ on:
http://www.softwolves.pp.se/misc/arkiv/cbm-hackers/0/0716.html
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Posted By
JamesC
on 2003-01-13
| Atilla -->
A preliminary test report has just been emailed. I have had the program just under an hour. I will try to do more tomorrow morning and tomorrow night.
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Posted By
SVS
on 2003-01-13
| Well, I will do the scans
but, please, be patient 
(I need to use hardware that I do not own)
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Posted By
JamesC
on 2003-01-13
| Atilla -->
I misread your post and thought it said 1:00PM.... which is noon my time.... I may look at it this afternoon if I get time, but I don't get off work til 7PM. I also have to be at work early tomorrow, so it'll be 36-48 hours before I can really work the program. 
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Posted By
Gaia
on 2003-01-13
| James C: sorry I meant 1:00 PM ;-)
[nt]
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Posted By
Gaia
on 2003-01-13
| Format
JPG is fine as long as you make sure that you set the quality to 100%, then it's
losless compression. Seeting the quality to ~80% however already makes the files much
smaller and still reasonable quality.
Could you experiment with it a little? My mailbox size is 5 MB, but please do not use the Hotmail account as it has got a 2 MB limit :-/
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Posted By
SVS
on 2003-01-13
| My schematics are "original" CBM engineered :) :)
and hand drawn too (no CAD or Computer draws).
Please Attila and James, specify me what resolution you can accept (= file size). The draws are on paper and not too dark (as ancient document!).
I think it is not the case to pack the scanned images with jpg in order to not less data/lines, then please indicate me the format (bmp, tiff, ...) you prefere.
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Posted By
Gaia
on 2003-01-13
| Schematics
SVS: If it's other/different than the ones to be found here, then please send it to my email address!
James C: As soon as I'm back home (around 1:00 AM, NYC time) I'll
send you the latest beta. I count on you
The big advantage of this port-level emulation is that it's far quicker
in terms of emulation than the CPU-level one. Furthermore, the 1551 in
itself is 3-4 times quicker than the 1541.
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Posted By
JamesC
on 2003-01-13
| SVS -->
I sure could use them, if they're notated in English.
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Posted By
SVS
on 2003-01-13
| Attila: I got the electrical schemes,
both internal card & cartridge card; do you need the scans?
S\_/S
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Posted By
JamesC
on 2003-01-12
| Atilla -->
I'd *love* to beta-test this!!!!
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Posted By
Gaia
on 2003-01-12
| Sheets and others
Oh, I see
I did so already for the TIA 6523 but haven't yet seen anything. Thanks again for the tip anyway!
I've just finished with an almost full port-based 1551 emulation in YAPE that is rather compatible. It seems that even some turbo loaders will work shortly... In fact anything could work with it as long as no B-E command (or similar) is issued on the emulated drive Would have been nice to add a CPU based 1551 emulation to the next release, but then I'll just postpone that part until I figure it out.
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Posted By
JamesC
on 2003-01-12
| 1541 vs 1551 IRQ
The IRQs are actually generated by one of the two 6522s in the 1541. I would imagine that the 6523 Triport Interface (in the cartridge housing) or the 6525 (on the circuit board with the 6510T) generates the IRQ for the 6510T.
I cannot see the processor generating its own IRQs. Sorry.
I do not have a cartridge port pinout schematic handy, but there is also the possibility that the TED passes an IRQ request to the 6523 through the cartridge port, and then the 6523 passes it down the line to the 6510T.
You might check the datasheets for the 6510, 6523, and 6525 at www.6502.org. I would right now but I have a crying 8 month old on one shoulder and a broken Adobe Acrobat reader on the other.
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Posted By
Gaia
on 2003-01-12
| Sorry to hear that :-(
Apart from points c, and d, it was known to me, too
It's a pity there's not much useful info on this drive anywhere. I'll dig a bit into the ROM disassembly then and see what I can find out.
I'm still curious about the interrupt source(s) on the 1551 and the exact role of the processor port. So, if anyone happens to know that....
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Posted By
SVS
on 2003-01-12
| I have the specific 1551 manual,
but inside it, you can found only a few specific information:
a) Error message 73 shows "CBM DOS 2.6 TDISK"
b) "&" command syntax (it works on 1541 too)
c) %R command (toogles between 8 and 9 device number [only "%" does a flip])
d) %S command (set interleave value [default=17])
Bye
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Posted By
Gaia
on 2003-01-12
| Disassembly
I certainly will! I've disassembled the ROM myself and now trying to figure out what's happening there.... There's not much useful done yet, but as soon as I achieve something I'll certainly share it with everyone for further analysis.
Interesting thing is that since the 1551 features a 6510 processor, it has got a processor port located at $00/$01 (the ddr and pr registers). The ROM actually seems to rely on it quite heavily (the IRQ routine, for one). It does not have a VIA 6522 unlike the 1541. It was replaced by the so called TIA 6523 tri-port adapter.
I also wonder what the IRQ sources were on a 1551, and how was the ATN line connected (on a 1541 when the ATN line goes low, it generates an interrupt in the 1541 CPU).
If you need the ROM disassembly in its current stage, just drop me a mail!
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Posted By
JamesC
on 2003-01-12
| 1551 manual
I have an original English manual but it is almost exactly a reprint from the 1541 manual. The largest difference is that there is no reference to BASIC 2.0, all examples assume you have a BASIC 3.5 machine (which would be correct for this drive).
I was disappointed in the lack of (new) information in this book. It does not document the %R and %S commands, nor does it have any *corrected* information that was misprinted in the 1541 manual. (Commodore US was not famous for their documentation.)
I also have a photocopied German 1551 manual which is just a 1541 manual with a '1551' sticker next to the '1541', to make it look like the manual says '1541/1551'. Obviously there was nothing new there either.
If you have a ROM disassembly for the 1551, then you have more information than I do. Is there any way you would be willing to share that with us, or point us to a download site?
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Posted By
Gaia
on 2003-01-12
| 1551 drive
I am just about improving the 1551 drive emulation in YAPE. However, I would need the user's guide as it might contain some extremely valuable information. I could not find much on the net and I am forced to figure out everything by myself from the ROM disassembly, which is rather time consuming...
Could anyone in the possession of such drive make a scan of the manual and send it to me? It would be _much_ appreciated!
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