500 Board

MK14HAK
Posts: 356
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Re: 500 Board

Post by MK14HAK »

Klyball wrote: Do you know if the cpu is even running?
Do you have a logic probe ?
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bxdanny
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Location: Bronx, NY USA

Re: 500 Board

Post by bxdanny »

Hi people. From the photo that was posted of this board, it seems to be configured for use with 540 video and polled keyboard. To use it with a serial terminal, the 65V PROM (the middle one, which is mapped to $FExx) would have to be replaced with a 65A PROM. The 65A code is available in one of the posts here, but burning one will probably be an issue. I expect that someone here could make one for you, though.
No current OSI hardware
Former programmer for Dwo Quong Fok Lok Sow and Orion Software Associates
Former owner of C1P MF (original version) and C2-8P DF (502-based)
falter
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Joined: Sun Dec 27, 2015 8:15 pm

Re: 500 Board

Post by falter »

Darn! I wondered if it might be that kind of situation. Yeah I wouldn't have a clue how to make one of those PROMs. Is that PROM specific to the 540 or could the 440 I have be used? Then all I'd have to do is find a backplane.
bxdanny
Posts: 311
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Location: Bronx, NY USA

Re: 500 Board

Post by bxdanny »

If you have a 440 (and a backplane), and the board is running, you should see the H/D/M? appear on the 440's video output. You wouldn't be able to respond, though, since the board would (almost certainly) be looking for a polled keyboard, which only works with the 540.

Maybe Klyball could burn a 65A PROM for you, or knows who could? Or maybe Dave knows?
No current OSI hardware
Former programmer for Dwo Quong Fok Lok Sow and Orion Software Associates
Former owner of C1P MF (original version) and C2-8P DF (502-based)
gekaufman
Posts: 72
Joined: Mon Nov 23, 2015 12:57 pm

Re: 500 Board

Post by gekaufman »

Just a note that I can burn 1702A's (or 2716's etc) here. I'd just need the appropriate .bin/.hex file.

I can actually program most any Eprom type, although my 2708 setup is a bit tenuous at present.

- Gary
bxdanny wrote:If you have a 440 (and a backplane), and the board is running, you should see the H/D/M? appear on the 440's video output. You wouldn't be able to respond, though, since the board would (almost certainly) be looking for a polled keyboard, which only works with the 540.

Maybe Klyball could burn a 65A PROM for you, or knows who could? Or maybe Dave knows?
Jeff
Posts: 370
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Location: British Columbia, Canada

Re: 500 Board

Post by Jeff »

I can program one too, I am located in western Canada, if that helps.
Image
Klyball
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Re: 500 Board

Post by Klyball »

Thats about the only one i can't do, i am always on the look out for a programmer that could do one but they are rare and expensive on epay .
i have schematics for a couple different ones but that's down the road and still pricey . a adapter would probably be the best solution.
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dave
Site Admin
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Re: 500 Board

Post by dave »

Martin Eberhard created a full-featured 1702A programmer:

https://groups.yahoo.com/neo/groups/alt ... opics/2599

I bought the PCB from him, and put together a nearly complete Mouser project for the BOM:

http://www.mouser.com/ProjectManager/Pr ... 7d4f9f4b97

However, I haven't yet built it up. It should only take an afternoon (without the case), one of these days. . .

Dave
falter
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Joined: Sun Dec 27, 2015 8:15 pm

Re: 500 Board

Post by falter »

I would totally pay for the efforts and costs of anyone willing to create the appropriate 1702 rom(s) for me. I throw in plural because I have no way of knowing really if the other roms are alive. Might make sense to burn a set of the correct ones for serial use.
bxdanny
Posts: 311
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Location: Bronx, NY USA

Re: 500 Board

Post by bxdanny »

Can EPROMS really lose their programming over the years, even with the window covered? Anyway, only two are needed for serial use, the 65A monitor program ($FExx), and the 65F3 reset code/floppy bootstrap ($FFxx), which is the same for serial and video systems (it reads the $FExx ROM to determine which it is running on). The $FDxx ROM is only needed for polled keyboard systems (or alternatively, a different ROM there for hard disk systems).

I was wondering what the distinction was between the 1702 and the 1702A. According to one source at least (http://www.jmargolin.com/patents/eprom.htm), the 1702 needs (or at least is specified to use) a -12V negative voltage, while the 1702A uses -9V. Since the OSI bus uses -9V, I guess it is a 1702A that is needed, despite the board description saying 1702.

FWIW, I am attaching files of the 65A and 65F3 code that would need to be burned. (At least I tried to, although there is no indication in the Preview that files are attached.)

BTW, Dave, if you are reading this, it is still not possible to attach files to private messages. I thought you said you had changed that.
No current OSI hardware
Former programmer for Dwo Quong Fok Lok Sow and Orion Software Associates
Former owner of C1P MF (original version) and C2-8P DF (502-based)
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