Womo, Is the schematic for that 6532>6530 adapter of yours available anywhere? TIA, mike ----- Original Message ----- From: "Wolfgang Moser" <email@example.com> To: <firstname.lastname@example.org> Sent: Tuesday, June 19, 2012 6:08 PM Subject: Re: Fun with 6530s and 6532s > Hi Gordon, > > gsteemso schrieb: >> Hi all, >> >> The current thread that discovered 6532s where 6523s had been expected >> reminded me of a project I was going to undertake... until I heard that >> someone was theoretically already doing it, anyway. I have a 2040 PET >> disk > > of course and theoretically I should have posted some progress report on > it, if you were talking about my post from August last year: > > http://www.softwolves.com/arkiv/cbm-hackers/15/15378.html > resp.: > > http://cbm-hackers.2304266.n4.nabble.com/Resending-Repairing-a-SFD-1001-8250-LP-8050-4040-3040-2040-td4072816.html > > >> drive (actually for practical purposes a 4040, as some prior owner >> upgraded the ROMs to DOS 2.0) with a defunct 6530 RRIOT. In theory, a >> 6532 >> RIOT and a small PROM can be combined on a little adapter board to >> replace >> a RRIOT, and in fact some later Commodore products apparently contained >> such an adapter board right from the factory. > > As Ruud Baltissen found in an attempt to reconstruct a KIM-1 and as I > can confirm, it is possible to "emulate" a 6530, if you know exactly > about the ROM contents and the PLA fuse matrix. In contrast to Ruud's > design I believe that I found a way to also reduce the 6532's feature > set to the one of the 6530 (don't allow IRQ generation via PA7). > > To make a long story short what happened meanwhile: > > * Nicolas Welte was in the need to let produce some prototype PCBs, > he was so kind to ask me on adding some of my 6530-to-6532 adapters > and I received 3 prototype PCBs of my design > > * The first assembled board worked as expected and the same way as > the wired raster PCB prototype which I had to debug for months > > * I had to relocate and all my projects were frozen for a while > > * Around Easter this year I was happy to find another NOS part seller > who claimed to be able to obtain some 6530 chips with a CBM part > number known for the 4040 or 8050 drive. Most other NOS sellers > that I tried before weren't able to actually to deliver, but this > one did. > > Martin Hoffmann-Vetter and I found out that at least one of the IC I > got, is a CBM part number whose ROM contents are not listed at > Funet/Zimmers yet nor elsewhere in the Internet. With some tricks and > the help of a slightly patched 6530-to-6532 adapter we managed to read > out the ROM contents of both chips. Still these read outs need to be > verified against a second pair of chips -- I ordered two chips from each > available CBM part number. > >> As I mentioned above, I understand someone has a project going to design >> such an adapter and make them available. In thinking about what such a >> thing would entail, it occurred to me that it should be possible to do >> the >> entire work of a RRIOT with a relatively cheap modern FPGA, including the >> ROM function. That's significant because just a 6532 by itself is usually >> $10 or more before shipping. > > So what's the good news on my NOS seller findings from above? These > chips did cost 10,- EUR each. In contrast to my solution where you need > to get an adapter board PCB, a TTL IC and a 6532 IC (currently sold by > Honkong/China part suppliers for less than 5,- EUR when ordering in > quantities), a 6530 with a CBM part number belonging to one of the CBM > IEEE floppy drives has the big advantage that you can at least repair > SFD-1001 and 8250LP drives very easily. These drives come already with > an adapter so that the ROM contents of the 6530 is replaced by the > contents within the EPROM. To repair such a drive with a defective 6530 > all you need to get is a working 6530 from _any_ of Commodores IEEE > floppy disk drive. > > If you need to repair any other CBM IEEE drive other than a SFD-1001 or > 8250LP you have three options: > > * Build a 6530-to-6532 adapter which is still not available from me > > * Have some luck to find a parts supplier that sells exactly the CBM > part number that matches your drive type and mechanism and the CBM > DOS version as well > > * Rip of the adapter board of a SFD-1001 or 8250LPT drive or perhaps > get a spare adapter board from somewhere else, replace the EPROM > with one that has the ROM contents burned in that exactly matches > your drive type, mechanism and DOS version, get a working 6530 > with a CBM part number for any of CBM's IEEE floppy drive and > voila the result would be a perfect 6530 replacement > > This works because to my knowledge all CBM IEEE floppy disk drive 6530 > ICs have the very same PLA "fuse map programmed" (actually it is a mask > programmed PLA, not based on fuses). The only difference is the mask > programmed ROM contents of these ICs. > >> Such a device as I propose would fit on a really tiny board that would be >> no larger than the original 6530 being replaced. Does anyone have enough >> knowledge of such devices to say whether I've had a good idea here or an, >> um, very much not so good one? > > On the long run, refactoring all these old chips into a hardware > description language is necessary. > > But for the moment I see lots of sources for the 6532 IC, either chip > pulls from old 6502 equipment other than CBM devices (my first Hongkong > order for 6532 ICs were such chip pulls) or meanwhile China suppliers > with factory new old stock ICs from Rockwell and others. > > And if this wouldn't be enough to refrain from starting work on a FPGA > based replacement, there seem to be some 6530 left over in 35 year old > stocks that wait for any buyers. Of course it's of course difficult to > find 6530 CBM part numbers that match most up to date DOS ROM version, > you always need to adapt the ROM contents onto an external EPROM, but > that's it. > > > Later this year I will try to write up more of the details about the > findings from Martin and me regarding the ROM contents of the analysed > chips and I also hope to find a way on how to provide some of you with > either adapter PCBs or kits. At least for the European area since I > believe Jim Brain would be happy to provide something similar for the > North American market. > > > Womo > > -- > ------ to obtain more infos about me, look up the page ------ > ------ http://www.wmsr.de | wm (at) wmsr (dot) de ------ > > > > Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2012-06-20 04:00:10
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