Re: [N8VEM-S100:4672] Re: S-100-16M-SRAM-MEZZ-V6c Board - Status --- OK

[Andrew Bingham <abin...@gmail.com>]

I was thinking of playing MS-DOS games at full 386 speed but with the I/O being S100 bus bound I'm not sure how well that would work over the S-100 bus vs ISA.  I know people have run the S-100 bus up to 10 Mhz and the main thing going over that would be an MS-DOS compatible VGA card which also worked on the ISA bus at 8 MHz so maybe it would work?

I have this idea of many years and hours of free time from now being able to play Wing Commander on a full homebrew computer build.  I guess it might be  "better" to design a 386 CPU board (or board set) for Sergey's ISA backplane (maybe with an over-the-top RAM connection similar to how you've implemented it) and be a bit more IBM PC-like....

Andrew B

On Tuesday, July 22, 2014 9:34:16 PM UTC-7, monahanz wrote:

I had not considered that Andrew, mainly because you need the two real mode ROM’s to get going.  You would have to either make a daughter board with (optimally) EEPROMS and place it at FFF000H or have RAM at that location, boot from the S100 bus, copy the real mode ROM to the to the top of the 4GB and go from there.  However in all case remember I/O is S100 bus bound.

It may be possible to rig up something with the current board controlling P20 pin 2,4 from a port (high inactivates S100 Access).   I will definitely look into it for the 80486 board.

 

John

 

 

 

From: n8ve...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Andrew Bingham
Sent: Tuesday, July 22, 2014 8:25 PM
To: n8ve...@googlegroups.com
Subject: [N8VEM-S100:4672] Re: S-100-16M-SRAM-MEZZ-V6c Board - Status --- OK

 

Good to know they checked out.  Not quite sure if I am ready to solder those yet, until I "need" them to go with the 386 board.

 

A question John - is it possible to tell the 386 board to go access ALL it's RAM on the Mezzanine/over-the-top-cable cards, so it stays in the "fast"  mode vs having the first bit of RAM on the S-100 bus?

 

Andrew

On Tuesday, July 22, 2014 6:09:44 PM UTC-7, monahanz wrote:

Todd just a quick note to let you know the  V06c version of the mezzanine boards checked out fine on the 16MG S100 RAM board.   I hammered them fairly good with the 80386 board, they did fine.

 

Soldering the chips on to the board is quite tricky.  I found it best to aligen one corner, then orientate the chip and do the diagonally opposite corner, then run the salder tip along the pins. With a wet tip there is enough solder on the pins and the board for contact.  However I had one chip where the pin did not make contact, took me a while to locate it.  These boards are definatly not for anybody with shakey hands

 

Will next do the 32MB 80386 board, but for now I feel confident sending them out to all 16MB board users.

 

Thanks Andrew and Dave for all your help on these.

 

 

John

 

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