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RE: [N8VEM-S100:2302] MSX2 Utility Board V1 Build info

Thanks Neil!  That’s great news!  Fantastic!  Tremendous progress!  I really appreciate all your effort and I think this is going to help a lot of builders.


Just what you have fixed so far would make a useful board to help boot a bare S-100 CPU!


Thanks for the many updates to the wiki page and those are looking really good.


I am looking forward to the next version of the S-100 Utility board with all the improvements and fixes included.


I think we are getting close to be able test an actual MSX CBIOS implementation. 


Dan Werner had one working on the N8VEM ECB system and I am thinking it would be a good starting point.


In the S-100 Utility board design some of the actual peripheral connections were kind of uncertain.


I am not sure how the cassette logic is supposed to work so hopefully we can get some help from the MSX gurus.


The matrix ASCII keyboard is kind of a mystery too.  It is not parallel ASCII but uses some kind of capacitive sense logic.


There might be a standardized part they intended for the keyboard but I was never able to get to the bottom of it.


My hope is the S-100 Utility board would be not just an MSX2 implementation for the S-100 bus but also a generally useful bootstrapping board.


Only the MSX requires Z80 but the RAM/ROM/PPI/UART logic is usable by any 8 bit CPU on the S-100 bus.


Although a 6502 based MSX computer is kind of a bizarre concept!  J


Thanks and have a nice day!

Andrew Lynch



From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of nbreeden
Sent: Tuesday, February 4, 2014 10:26 PM
To: n8vem...@googlegroups.com
Subject: [N8VEM-S100:2302] MSX2 Utility Board V1 Build info


Status of my MSX2 Utility Board build.


  I've made enough progress on the board be able to run a simple monitor out of the on-board EPROM. I've had to make 2 changes to the board for this. These changes are documented in the file area under "Builders Journals\Neil B"


  Based on my work I believe the following are working (based on the fact that my monitor is running out of the utility board EPROM/RAM using the UART to communicate).

    * 8255 PPI

    * 16550 UART

    * 32K EPROM at $0000-$7FFF

    * 32K RAM at $8000-$FFFF


  Still waiting to be tested:

    * Printer Interface

    * RTC

    * Slot Selection Logic

    * Remaining 32K RAM (mapped in the slots)



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