More good news Guys. I now have our 80286 S-100 board running at 12 MHz (no wait states) with our 4MG Static RAM board.
I noticed that my bus controller (U68) was a 82C288. Looking around here I found I had an 82C288-10. When I tried that, the board came up fine at 12MHz (no wait states). Clearly the CMOS clock generator while rated for 10MHz, works at a higher speed. The original 82C288 I think is for 8MHz, pushing it to 12 was too much.
Fortunately I already have a 12Mhz clock generator (28C284-12) on board.
I see there are PLCC 16MHz AMD chips. Does anybody know where to find these chips and the corresponding -16 clock generator and bus controllers.
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of David Fry
Excellent news :-)
I was kinda holding off on starting my 80286 board in case the mods/fix ended up being extensive (I have the S-100 Ram/Rom board on order also)
Just wondering if will you be investigating why the final board will only manage 11Mhz when the prototype manages 12Mhz ?
It's not a big issue but would be nice to get to 12Mhz if possible.
regards and thanks