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Re: 16-bits giving me fits (and other rhymes)

All —

Ok, I’ve made a bit of progress this afternoon. I started from scratch with my trusty IO4, the Z80 board, the 4mb RAM board (with bank 1 enabled; rest disabled) and the stock Master 4.8 monitor with minor modifications for the console board (status bits). Now I have the stock Z80 monitor working.

I went through the 8088 jumpering again and I’ve gotten it to the point where the Z80 will hand-off to the 8088 but then it goes into La-La land. I have the 8086 monitor (version 10.33) installed, again, with the minor mods for the IO4 (but port 2 so I can watch it on another terminal window).

Instead of using 0 as a fill-byte, I’m using 90H (NOP) so that if the code maps into the ROM wrong, it will zoom along until the first JUMP. I think I really need a sanity check on the jumpers because something is still amiss.

Thanks again, in advance, for any help.


From: Richard A Cini <rich...@verizon.net>
Date: Sunday, November 23, 2014 at 12:22 PM
To: S100-Post <n8vem...@googlegroups.com>
Subject: 16-bits giving me fits (and other rhymes)

All —

I spent most of yesterday trying to get some sort of 8/16-bit hybrid system working using both new S100 Computers boards and some vintage stuff. The closest I came to having it working was the following: RAM22 (8/16-bit), SCP-200 8086, MSDOS Support (for the ROM) and my SSM IO4 serial card. In that case, I can get only console output — the monitor will not receive input. I suspect maybe that the 16-bit data buss is causing the problem, but who knows.

So, I stripped the system down to the SSM serial card, the RAM22, and the S100 8088 master/slave card. It still doesn’t work and now I don’t get any output at all. I tried to follow the instructions to make the 8088 card a “master” but I think there are some inconsistencies in the instructions. For example, it says to jumper K10 for 1-2, but this grounds the output of an 'F04 inverter. That doesn’t seem right. I’m sort of encouraged because the M1, MREAD and MWRITE LEDs are lit, so something is working.

Does anyone have the 8088 card working in master mode? If so, can you maybe send me a picture of the jumpers so I can compare it?



Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator