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RE: [N8VEM-S100:5482] MSDOS Support Board V2 questions



Yes a typo, there is no K1 on the V2 board. The equivalent (Phantom*) jumper is JP5 on the V2 board. Will correct the web page.

On K5, this is the way IBM had these pins on their original PC motherboard. Not sure why or what for!

JP6 is to insure the critical Open Collector  S100 bus line sINTA has at least one pull-up somewhere on the bus.   There should only be one. If you have multiple CPU cards, make sure only one is pulling the line up (and in fact,  all other CPU driven S100 OC lines).  Normally our Z80 CPU board does this.  So usually – unconnected.

For MSDOS to boot etc., the P39/P37/P53 jumpers are not used. The RTC is used to get the actual date/time on boot up,  but the 8254 interrupts keep track of time after that.

I actually use our Console I/O board keyboard input (with S100 bus, VI1*)  for MSDOS.   Should be VI1 direct to the PIC for MSDOS/IBM PC compatibility.

 

Good luck with it.

John

 

 

From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Richard Cini
Sent: Friday, October 31, 2014 8:18 PM
To: S100-Post
Subject: [N8VEM-S100:5482] MSDOS Support Board V2 questions

 

All —

 

                I just finished assembling the board, testing as much stuff along the way as I could with the Z80 board. Things seem to work fine, but I have a few clarifying questions. I hope to use this board, initially, as a proxy for the Seattle Computer Products CPU Support Board as part of a system re-creation/demo project I’m working on. I have the SCP-200B 8086 board, the Cromemco 16FDC, an SSM IO4 (console card) and a CompuPro RAM22 (which subs for several SCP 16k memory boards). I hope this will approximate the system Tim Paterson used to create 86-DOS.

 

                Here are my questions:

  • The EEPROM configuration and test procedures for the V2 board mention jumpering K1. There is no K1 on the V2 schematic or on the board (that I can find). Is this a typo? I found all of the other jumpers in that procedure.
  • Jumper setting for K5 isn't mentioned in the procedures (assuming not jumpered).
  • Jumper setting for JP6 (4.7k pull-up on the board select line) also isn’t mentioned (assuming not jumpered).
  • Default jumpering for P39/P37/P53 (VI settings for the RTC). Assuming not used.
  • How are people connecting the keyboard interrupt (P54.15) to VI1 (P54.4)? I would assume wire wrap wire but I wanted to check. Important for MSDOS.

                Are there any other gotchas I should be aware of? Thanks!

 

Rich

 

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Rich Cini

Collector of Classic Computers

Build Master and lead engineer, Altair32 Emulator

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