On 11/19/19 11:19 AM, Herb Johnson via vcf-midatlantic wrote:
[ebay] for 2 1979 Motorola 68B09 boards (looks to be an Exorset board).
Neil, I think you and I have talked about these boards before, and I saw the auction. I have an EXORbus system myself and some interest otherwise in these early 8-bit busses. Consider bringing a board for some show-and-tell at Festivus; we can figure it out and show how that used to be done.
I'll bring a bunch of boards (geek pron) but none are for sale (Keeps your mittens off my 8 bittens ;-) Hey I'm an engineer not a poet). I've actually spoken about these and a few others. The one I missed was the incredible one with the trick op code insertion and the 2K of DAT (a more advance version of the 74189 built DAT). I actually heard about that one back in the 80's. Always thought that was so cool. I'm also up for some reverse engineering learning. I have a board I helped design (a 6809 board) that I don't think I have the PAL equations for any more. That blank board seems to be quite tricky as a trace with a voltmeter on address bus doesn't seem to go where I expected it would. The set I just got are the simple Motorola reference design (or close to it). I suspect it won't take much to get ASSIST09 on the board.
Regards, Herb "we don't need no steenking schematics" Johnson
Actually walking the high 4 bits of the address lines will probably give us the start of the memory map by checking the chip select. As long as they didn't get to funky with clock matching. That can add to the fun. -- Linux Home Automation Neil Cherry ncherry@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies