Gary, just made an interesting observation with respect to the V3 IDE board/80386.
I have been doing a CPLD driven (V2) version of the 80386 board recently. All things work fine within the 80386 monitor including the critical interrupt tests etc. But very interesting, when I went to boot MSDOS with the V3 IDE board it would not boot. Worse the 80386 monitor command “N” would not even initialize the V3 IDE board. When I went back to the V2 IDE board, the “N” command worked and I could sequentially read sectors etc. Interesting however I could not boot MSDOS. It hung, but this may be with other issues (RAM access etc.) on this prototype 80386 board. Remembering your problem, I dug up an 80386 board with an AMD DX-40 chip instead of a Cyrix-40 chip. To my surprise that CPU board would not boot MSDOS on the V3 IDE board. It looked like it was doing fine. I see the diagnostic :- “Boot Sector Loader Signature Valid <AA55H> Now Booting MSDOS….” But then I always get a Int #6 (Invalid Opcode) Fault. The old V2 board works fine! There are many variables here. Probably some subtle timing issue. I’m inclined to start with the V2 80386 board. I will have to trace where in the IDE board initialization the monitor is hanging. I’m suspicious of Ints coming into the 80386 for MSDOS for the V1 80386 board. May dig up CPM86 (interrupt free) and check that out. Wait states on the V3 IDE made no difference. On all these 80386 boards the S100 pWR* is very touchy. Not a lot of control on, when and how long, on the V1 board, but I have fine control on the V2. These types of things are the worse type of problem because of the number of possible variables. If you notice anything let me know. John From: [email protected] [mailto:[email protected]] On Behalf Of John Monahan Sent: Wednesday, July 8, 2015 3:30 PM To: [email protected]; Gary Kaufman Subject: RE: [N8VEM-S100:7372] 80386 Jumper Check... Hi Gary, I’m back! I attaching a (large) detailed picture of the 80386 board which shows the jumpers etc. I used. With the Cyrix chip I could squeeze 40MHz out of this board. It has no problem running with the V3 IDE board. The wait states can in fact be squeezed lower I seem to remember with our later RAM boards but it’s been a while. I am actually working on a better, V2, CPLD driven board as we speak. That one will be simple and have much better configuration capability. In your case how far do you get with the IDE board. Can you use the 80386 monitor IDE board diagnostic commands? John From: [email protected] [mailto:[email protected]] On Behalf Of Gary Kaufman Sent: Tuesday, June 30, 2015 7:48 AM To: [email protected] Subject: [N8VEM-S100:7341] 80386 Jumper Check... I have the Z80 and 8088 boards working nicely with the IDE V3 board, but still can't get the 80386 board to work. Could anyone who has the 80386 board confirm that I have the jumpers set correctly? - Gary -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
