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RE: [N8VEM-S100:1583] S100-68K-V3 -- A brake at last!

Thanks John!  That’s great news!  Yay!



Now that the S-100 68K CPU board is working I’d like us to consider either a PAK68/2 and/or PAK68/3 for it or a 68030 native board.


Especially one that could use the top connector for the 8MB or 32 MB SRAM board.


I am thinking a 68030 native board would be about the same complexity as the S-100 80386 CPU board and even share elements of the design.


Thanks and have a nice day!

Andrew Lynch


From: John Monahan [mailto:mon...@vitasoft.org]
Sent: Friday, April 26, 2013 2:00 PM
To: n8vem...@googlegroups.com; 'yoda'
Cc: Andrew Lynch
Subject: RE: [N8VEM-S100:1583] S100-68K-V3 -- A brake at last!


Good news guys, finally got a brake on the 68K board. Now have it working R/W S-100 RAM (4MG Static RAM board) with a 12MHz oscillator (bus clock 6MHz).


The problem is embarrassing, a poor solder joint to ground on U32!  You would think by now I would have seen this earlier. Should have check more carefully before the build – I never learn. My tip-off was that an old Godbout 64K RAM board worked fine – did not require upper address lines!


Feel somewhat relieved, but we are still not out of the woods. At these speeds the board does not work reliably in the extender board (but OK at lower speeds). In contrast the 8086,80286,80386 have absolutely no problem far higher speed (bus clock 10-12MHz).  Timing is clearly tight. I will try and tweak things. Dave,  since you are almost there, for me – P2 16-15 jumper halts  everything. Does it for you?


Stay tuned