Antronics(Microsystems Ltd) SS_040-3 (6803_Microcomputer) Single Board Computer

[ortek_service]

Another 680x board, but which I can find very-little info on at all.
- Only found this short product (P)review, here, from this pdf download page: (Cropped & full page pdf's attached)
https://kundoc.com/download/memory-m...71804a2f1.html

There is currently an 'Antronics' company in Hampshire, but it seems they've only been around 20years and so probably not related to Antronics (Microsystems) Ltd London SW20 manufacturers of this 1983/84 IC's dated Eurocard
- That has a 64way 2 row DIN 41612 Type B?connector, with power-rails at either end (But not sure if it is compatible with Acorn System etc.- The 6821 PIA looks to connect to most of the upper (b) row although end-eight go to the MC6803L CPU pins 13-20 = port-lines P10-P17?).

Unfortunately the NV-RAM appears to have lost any contents after nearly 40yrs (I think they were rated for 5 / 10yrs? retention) - One I tried(IC6) read back (using 2764 EPROM as IC-programmer's device selection type), just all 0's.
However, I did manage to read the (Address decoding?) PROM - labelled 'Just IC6 En.' - .Zip Attached, as well as for photos's

So I wondered if anyone has encountered this particular one / manufacturer before?

[Phil__G]

I have some of those Greenwich NVrams too, some still retain, some are dead, and some work as a 6264 ie work ok but no power-off retention. I found a doc that explains where to dig the 2 cells out, bought a diamond holesaw, but gave up after breaking two...

[ortek_service]

Yes, I tried cutting into the sides / top of one of mine, but they are rather hard-epoxy potted so difficult to get to the cells compared wth some other RTC+battery types, that it seems you cn just remove the potted battery off the top fairly-easily and replace with a coin-cell holder etc.

Although I did find this article on how to do it with the 2K ones:
https://www.retrobrewcomputers.org/f...ree&goto=6707&

I did find that JPG Electronics are selling > 20yr old ones of these on a certain Auction site at £8 each! - With them saying the battery is probably dead as >>10yrs old, but could just use them as normal RAM IC's (A rather expensive 6264!)

These NVR8's do have an unusual nInhibit pin, on the end of the package - See attached datasheet.

Back to the actual bus connections on this, I've now traced all the pins and found the only similarity with the Acorn system (apart from actual connector), is that main CPU signals bus are on A-row (with B-row is used for GPIO from PIA + 6803 uC built in ports), and power / Gnd on the end pins of A-row - But with opposite polarity to Acorn system!
- See attached PDF print of connections table (Not sure about pasting an excel table into here, and keep the formatting)