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jpolo
April 10th, 2017, 12:53 AM
I have this card that came with an IBM 5150 (http://i.imgur.com/ycgwaCT.jpg) I found at a flea market a few years ago that I'm just starting to work on

http://i.imgur.com/vbodqZa.jpg (http://i.imgur.com/HZtptJK.jpg)
(click for big)

It has a few functions:

- 256k of expansion memory (with the ability to use as a RAM disk)
- Serial and parallel ports
- Realtime clock
- A terminal emulator in ROM

When I got it the clock battery had leaked (but there didn't appear to be any corrosion spreading at the time) so I removed the battery, and then I put this and all the other 5150 stuff away because I didn't have a monitor that could display MDA/Hercules (it came with both, Hercules installed and MDA in the box the Hercules came in). A while later I got a trisync CRT for a different system, which still isn't MDA compatible but I found an EGA card in my parts drawer so I was able to fire up the machine. It booted fine when configured just to use the 256k of RAM on the motherboard but when I set the jumpers to 512 to include the 256k on the systemcard I got the 40XX 201 error, meaning it couldn't see any RAM above the 256k onboard. I noticed some corrosion I had missed on the legs of the 8250 UART (large chip next to where the battery was) so I pulled it out to try to clean it and some of the legs were so badly corroded they popped off. I ordered a replacement 8250 and this got the 5150 to see the full 512k of RAM. A few days later I got a DOS boot disk and ran debug, which showed the serial port and parallel port were where they should be at 03F8 and 0378.

One of the many floppies that came with this system was a Kraft driver for a serial trackball (https://i.imgur.com/jPCBgy9.jpg) and a copy of a paint program that Kraft bundled with it, but no trackball. I wanted to mess around with this and also figured it would be a good way to test the Systemcard's serial port so I found that model of trackball cheap on ebay. Now I have it but I'm having problems, the driver refuses to load. It has a few command line options:

C# - Specify COM 1-4
Z - Use Aux port
T - Transpose IRQ (between 3 and 4)

When trying to specify the (any) COM port I get the error "COM(X) is not available"
When using the Z option I get "Aux port not detected"
When running with no arguments I get "Mouse not detected"
The transpose switch has no effect on any of these.

There's a bank of 8 DIP switches on the Systemcard, and I can't find a guide to them anywhere, which I find really weird for a Microsoft product. Through trial and error I found that SW6 changes the COM port from 1 (03F8) to 2 (02F8) and SW8 changes LPT from 1 (0378) to 2 (0278). Switches 1,2,4, and 5 seem to have something to do with RAM as I get 201 errors if I mess with them. SW3 is strange as when it's off I get nothing on the display (but the PC still boots and seems to POST). SW7 doesn't seem to do anything. Regardless, changing the COM port address did nothing for my problem. The configuration the switches were in when I got the card, and what works as far as memory and debug seeing the ports is 11100101. I should note that right now I have no way to get any other software on this machine so I can't test other drivers etc. I did test a generic serial mouse that I know works and got the same result. The only other card in the machine besides the drive controller and EGA is a Kraft Joystick port, and removing it doesn't change anything.

I'm wondering if anyone more knowledgeable than me regarding truly ancient PCs could shed some light on what's going on here, or if anyone has the manual for the MS Systemcard, I'd be really interested in reading the whole thing but even just the DIP switch settings would be a huge help.

modem7
April 11th, 2017, 02:43 AM
I see that the card has "Designed by burtronix" on it.

I presume that the connector for the serial port is the smaller of the two connectors. If so, because the card was designed in 1982 (i.e. prior to the 9-pin serial ports introduced in the IBM AT), burtronix may have used their own pin-out on the serial port connector.


I should note that right now I have no way to get any other software on this machine so I can't test other drivers etc.
Pity. I was going to suggest the use of a particular serial port testing tool to verify that the serial port is in fact using IRQ 4 (as the jumper setting suggests).

jpolo
April 11th, 2017, 06:52 AM
because the card was designed in 1982 (i.e. prior to the 9-pin serial ports introduced in the IBM AT), burtronix may have used their own pin-out on the serial port connector.

Wow that's a great catch, I never would have thought of that. I googled around for burtronix and found that namesake Don Burits has spoken to retro computer fans (http://drop-iii-inches.com/2017/01/21/episode-18-don-burtis/) about Apple /// stuff, so I shot him an e-mail with a link to this thread to see if he can shed any light or has some old manuals around.

Great Hierophant
April 11th, 2017, 08:15 AM
I have this card that came with an IBM 5150 (http://i.imgur.com/ycgwaCT.jpg) I found at a flea market a few years ago that I'm just starting to work on

http://i.imgur.com/vbodqZa.jpg (http://i.imgur.com/HZtptJK.jpg)
(click for big)

It has a few functions:

- 256k of expansion memory (with the ability to use as a RAM disk)
- Serial and parallel ports
- Realtime clock
- A terminal emulator in ROM


A terminal emulator in ROM? I don't see any ROM chips on the board.

jpolo
April 11th, 2017, 08:41 AM
A terminal emulator in ROM? I don't see any ROM chips on the board.

I got that information from here: http://uk.pcmag.com/desktop-reviews/62082/gallery/the-secret-history-of-microsoft-hardware?p=4

And yeah it's not even mentioned on offical ads I could find for the thing

evildragon
April 11th, 2017, 08:52 AM
Correct, terminal emulation isn't in ROM. It's a piece of software: https://books.google.com/books?id=4S8EAAAAMBAJ&pg=PA54&lpg=PA54&dq=microsoft+Systemcard&source=bl&ots=y5kGIif1kn&sig=S5MJSav4oHW9zCyuGKZoboo6oDw&hl=en&sa=X&ved=0ahUKEwimz9Oj7pzTAhUKNSYKHUomDNYQ6AEINTAC#v=on epage&q=microsoft%20Systemcard&f=false

jpolo
April 12th, 2017, 01:32 PM
Here's an e-mail reply I got from Don Burtis regarding the card:



Wow, this really is an oldie! Very rare, too, as Microsoft exited the IBM compatible card market almost as soon as they entered it. Yes, I did personally design this card (and many others for Microsoft back before they had any hardware engineers). Sadly, I do not have any records of this design (nor the switch settings).

I doubt I would have used a non-standard 9 pin serial pin out - more likely I had advance knowledge of what IBM was planning for the AT, and/or there might have been an IBM serial card for the 5150 that used a 9 pin connector.

In the photo, I was not able to read the part numbers on the two small ICs near the 25 pin connector. Can you send me their numbers (close-up photo would be even better). I'm totally swamped this week, but could do some detective work on this next week. The problem might just be a baud rate mismatch.

Although I designed the board in 1982, this (your) board was built in early 1983 (based on date codes of some of the ICs).


I've sent him a close up of the ICs he's referring to (UA75150TC). He also pointed me to some Burtronix slot extenders (http://www.ebay.com/itm/332163140763) for the 5150/XT/AT he has on eBay, which I have no use for but I figure someone here might be interested in.