5 Aug
2013
5 Aug
'13
6:04 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Alexandre Souza
Sent: Monday, August 05, 2013 7:59 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Looking for MSX2 expertise
my
Honestly, I don't know much of anything about
MSX.
You should! This is a **very nice** computer for mostly anything.
I'd reccomend you to take a look at something if you have time:
- BlueMSX emulator and its source code
- MSX Datapack (3 huge books in japanese, but some info and schematics
well detailed in English)
- MSX Techinical Handbook (you can find an excellent scanned copy at site:
http://www.tabalabs.com.br/msx/msx_tech_hb/)
right
Assuming we start with this as our baseline
configuration 1. N8VEM 8
slot active termination S-100 backplane 2. S100computers.com and
N8VEM S-100 Z80 CPU board 3. S100computers.com and N8VEM S-100 VDP
Are any changes necessary to the above boards to provide MSX and/or
MSX2 compatibility?
I need to study the schematic of the boards. I'm travelling for work now. I'll download them and take a look.
you
What else would be necessary to complete MSX
and/or MSX2
compatibility? I assume some sort of S-100 board with 64K SRAM + IO.
Probably a cartridge port, couple 8255 PPIs for control and ASCII
keyboard and a serial port for a mouse? Is there any sort of
interrupt controller or DMA controller?
The MSX is way simpler than that. Basically (for MSX1 compatibility) needs:
- A Z80 processor clocked at 3.579545MHz
- A AY-3-8910 chip (sound processor, but also used for cassete input
[!])
- A 8255 PPI
- A TMS9128 (or compatible - you can use 9938 or 9958 processors since
they are a superset of the 9128) video processor chip
- At least 16K of RAM (preferably 64K)
- A little of glue logic :o)
Everything else is an expansion and MUST be glued to the expansion
bus.
We can reuse the S-100 bus interface
"glue" from other boards. What I
am looking for is the components necessary for hardware compatibility.
Maybe, but what is the objective of the project?
- Create a MSX?
- Create an add-on board for MSX compatibility to an S-100 computer?
- Creating something new? :D
Greetings from Brazil :) From what I read above it sounds like there needs to be
a clock signal tie
in from the V9938 VDP to the Z80 CPU clock to supply the 3.579545
MHz
signal. It is emitted from the V9938 if I recall correctly. I am thinking
an "over the top" style wire jumper with the Z80 CPU board next to the VDP
on the S-100 bus.
Also the ongoing design of the S-100 VDP V3 may need to be modified for
cassette IO functions. How are those implemented? There are spare GPIO
pins on the AY-3-8910 so it makes sense if we are talking about motor
control, Push to Talk, etc.
A simple 64K SRAM + IO (8255 PPI + UART) would be perfect for not just MSX
compatibility but for builders in general as a CPU board debugging tool.
Thanks and have a nice day!
Andrew Lynch