Mini680 Altair 680 Memory Expansion Board

[bugman]

Hey Grant,

Received my kit today, thanks. Just wondering if you could post that memory information. When I get my kit built, I'd like to start working on the memory upgrade (unless you plan on having those in the near future). I found some plans for a simple 32k expansion for the 680 swtpc. But I'm not sure if it is 100% compatable with the altair, or how I would interface it. It uses an expansion slot, where as you use the clever IC replacement method.

Any help or direction would be appreciated.

Thanks,
Brian

[Grant Stockly]

No problem. I was going to include assembler listings in the manual but it would have been a lot of pages for only a few people.

I have written the monitor, boot loader, flash read/write routines, and page code in modules and I have batch files that assemble the batch files into one big file for a chip burner.

I DO have a small program which writes one 8k block at a time for people wanting to add their own programs to the 680.

Look in the manual at the end of my color guide for a quick intro to the special functions in my modified monitor. Its possible to boot basic with only a few key strokes and 5 seconds.

Booting basic the vintage way involved 13 minutes with a tape cassette player OR 30+ minutes with a paper tape reader. (and you weren't guaranteed that it would work the first time!)

[Grant Stockly]

I've been intending to get this information to you guys for a while. I wanted to wait until I could clean up the information and make it more presentable, but if I did that then it wouldn't be out for another 6 months!

So, here is a zip file with all of the data that I used to make the memory device. There are assembly files, batch files, hex code files, binary files, etc. I'll try to describe how it works. I never made it a clean process, just "got it done" for the memory card and moved on.

[Grant Stockly]

Here are the files. I will try to make sense of them and describe what I did in a little bit. : )

The assembler code for writing to a page is in flash_burner.asm, look at the file for start/end offsets. The KNOCK macro disables write protection for a single page write.

flash_mon.asm is the stock Altair 680 ROM monitor modified for use with the flash memory.

flash_boot.asm copies the ROM monitor out of flash and into memory for execution.

page_set.asm is located on every single flash page except 0. If the computer boots up with the page register in something other than 0, this code will cause it to go to page 0 and execute the monitor.

I will describe everything required to assemble a new rom set or patch the flash with a new memory image later...

[jackrubin]

Hi Grant - are any of these boards still available?
Thanks,
Jack