1225Re: [midatlanticretro] Which version is it, Altair 680 or 680b ?
- Sep 5, 2005Dan,
I should say that I could be totally wrong...I don't have a 680, but I have
seen in a couple here and there. I actually read about the B when reading up
on my SWTPc 6800. I can't remember exactly where. Definately the IC L was
made with a blank on the "B" unless you added the optional serial ROM for the
slot. I don't know if the non-B 680 would have the slot or not, but I would
focus on that part of the card, try to find a schematic that compares the two to
get your answer about the rev of your particulat 680.
In a message dated 9/5/2005 8:56:32 AM Eastern Standard Time,
> I couldn't tell which month in '76 this mainboard might have been made.
> Is yours a 608b too then ? I was hoping the Rev # would give a clue. The
> mainboard does have a place for IC L (74LS74), but the socket is empty.
> So would the 680 version have a blank spot there w/o any traces ? I
> recall seeing pictures online of the early 680's with a beige front
> panel, mine isn't. I guess then this might be a 680b after all.
> I think my brother never ordered this with the Monitor Rom, because that
> socket is empty. The System Monitor manual still has the source code in
> there. The title in there mentions 680b Prom Monitor. I'll have to try
> and dig up some 1702 Roms and program some, I hope I get a good one.
> This might be a good time to build a rom emulator.
> I think I remember why now we had to build an ascii keyboard w/ parallel
> intfc for this. We didn't have a terminal back then to use if we had a
> Monitor Rom. So we had this wired up to the machine as an I/O port
> instead. Looking through some of the code listings on an old notepad, I
> found a code listing for a Monitor code which allowed us to read from
> the ascii keyboard. Basically, this code was modified from the original
> Monitor Rom and skipped over the ACIA serial chip instead and read from
> a memory-mapped I/O port.
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