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Swtpc 6809

TanruNomad

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Not exactly an S100, but I recently acquired a SWTPC 6809 (model 69/A meaning it was pre-assembled, not sold as a kit). I've never programmed for or even used a 6809-based machine, but based on what I've read it was fairly advanced for the time, more so than 6502. I have a few questions about this thing:

1) What's the difference between this computer and the S/09?
2) Where could I purchase the 5.25" or 8" floppy disk drives for it? Or are there more contemporary storage options?
3) SWTPC sold two terminals for it: CT-64 and the CT-82, but would a basic RS-232 ascii terminal be fine or were these graphics terminals?
4) Is there a 6809 community? Any other SWTPC 6809 users here? :)

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Chuck(G)

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Must have been close to the last gasp for SWTP--a nice clean specimen!

Do you have the DC-1 controller card in your system? If not, I suppose that you could even construct on on perfboard--I think that WD1771s can still be found. The rest is just a plain old 360K floppy and power supply--not hard to construct yourself.
 

smp

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Oooooohhhhhhhh!

I am sooo envious!

Congratulations on a great acquisition. Any more of those available out there?

;-)

smp
 

deramp5113

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Looks great! The 6809 was such a step forward in the 8 bit processor instruction set. I'd love to pick up one of these.

Mike
 

daver2

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You may find the following links handy for the manuals on the terminals you identified (http://www.swtpc.com/mholley/CT_64/CT_64.htm and http://www.swtpc.com/mholley/CT_82/CT82_Index.htm) and in general "http://www.swtpc.com/mholley/" for all things SWTPC-related.

I had an opportunity to obtain some SWTPC 6800 equipment a while ago from Australia or New Zealand (can't quite remember which). Unfortunately, shipping costs to the UK were (not surprisingly) astronomical! He may still have it if anyone is interested in the contact (but note 6800 not 6809 - or did he have some 6809 equipment as well? - I will check my facts if anyone wants to konw).

The Commodore SuperPET (aka SP9000) had both a 6502 and a 6809 processor. Fairly hot on the SuperPET if you need any help with the 6809 processor itself - but the software was from Waterloo University in Canada (BASIC, COBOL, FORTRAN, ASSEMBLER, PASCAL and APL) with no real operating system in it at all.

Dave
 

TanruNomad

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Thanks for all the info guys. Definitely need to read up more on this. The unit is non-working which I knew when I got it, but it will be a fun project when I get some more time. Unfortunately, this was the only SWTPC unit there. I went ahead a removed all 8 cards and took some quick photos with my phone. Counted only 4 dead spiders, not bad.

Here's the album: http://imgur.com/a/ULDy5#0
 
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daver2

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Well done that man :)

You seem to have a pretty full system there...

Most of the cards are documented on mholley's site - some under the 6809 section, some under the 6800 section and some under the disk storage section.

You seem to have:

A couple of MP-M cards (4K static RAM).

A ROM board that I have never seen before (may not be SWTPC?). Thanks to the previous owner for not labelling the EPROMS!

An MP-A 6800 board for some reason! Three of the chips are missing and some of the legs of the chips are bent out. Did this card ever go in this system (to make it switchable from 6800 to 6809) or is this an 'extra' card I wonder?

The MP-09 6809 card with SBUG monitor.

A DMF2A single and double density disk controller.

A couple of 32K RAM boards.

An MP-R 2716 (5V only) EPROM programmer - but as your ROM board uses 2708s this may not be that useful (unless you can change the ROMS to 2716). Note that 2716 EPROMS came in 5V only and multirail power supply versions - only the 5V device is suitable for programming on this card.

An MP-S2 dual serial interface. I note that this card has an 'optional' IC installed in position IC 9 which permitted four separate 'digital inputs' to be read from the pads immediately to the left of the IC.

I would suggest downloading all of the manuals and images from http://www.swtpc.com/mholley/ relevant to your system, buying a hardbacked notebook and thoroughly documenting the link and switch settings from all of the boards and which slots on the backplane the cards were in. You should then look at what all the switches and links do in the manual to identify how the equipment is currently configured.

I would be inclined to look a bit more closely at all of the cards with relation to the documentation to see if any of them have been modified.

I would then think about bringing up the power supply on its own without any of the cards and measuring the voltages to make sure everything is OK. You may want to consider changing any electrolytic capacitors in the power supply anyhow as they may have degraded and have a tendency to bang!

Install only the minimal set of cards to make a working system first (depending upon the configuration of the cards of course). If you change any of the links or switches - thoroughly document what you are doing and why. This will make it a bit easier when adding further cards later to set the configuration back again if you changed something.

One word of warning. I have found from experience that testing the voltage regulators on the cards outside of the chassis (I connect mine to a variable power supply) to make sure they work before plugging them in. I have just got into the habit of doing this. I found a card once with a shorted +12V regulator - so that would have put the +16 to +18V (this was an S100 system) onto the 12V rail of a card - not doing it any good in the process! Swapped regulator, card worked OK - no black smoke!

Before messing though - read as much as you can first so that you don't damage such a great find!

Good luck.

Dave
 
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