From: "river" <river at zip.com.au>
Sent: Tuesday, June 14, 2005 1:23 AM
Hi,
Great, thanks for the info.
I'm sourcing a few S100 protoboards, so I'll be able to wirewrap a board
with all the relevant RAM, ROM and I/O. I'll probably use later generation
chips such as 62256 for RAM and 6264 for ROM. I can then put in the 8251
and 8255 for serial and parallel ports, respectively. Is that heresy in
regards to these old boards?
It's not an issue to me starting ROM at 0000h. I've written a few 8080
debug/monitors for my old Multibus stuff so I can always use one of
these - or mod it accordingly.
I've only got a 6-slot motherboard and a Northstar ZCB processor board,
S100 ROM board and some Dynabyte RAM boards and I was going to use the
motherboard and original S100 boards with this system. This means the
8800CPU board will be in a small 2-slot system - the CPU board and the
RAM/ROM/IO board I'm going to make.
I'll check the MWRITE signals and see what I can do, or if you have the
info then that's even better.
Just one more thing.... I suppose it's possible to use the 8800CPU bd
without the power regulation components if I ensure the correct voltages
go through the correct pins on the bus. I can then use an old spare PC
power supply, instead of creating a new supply. Naturally, this would
entail that no other S100 board can be used due to their on-board
regulators. This isn't an issue if I build my own S100 boards, without
regulation, for this system.
Again, thanks for your help. This is my first foray into S100 stuff, and
makes a nice change from Multibus.
rgds
river
A few manufacturers used S100 bus with regulated power supplies including
some CompuPro systems. It doesn't hurt anything to plug in a card with
onboard regulators it just won't work without bypassing the regulators.
Mwrite is pwr nor pout, memory cards can use pwr I/O cards can use pout but
a 7402 can generate mwrite.
The NorthStar CPU can do most of what you want. If you piggy back RAM and
EEPROM and add a little logic then all you need is I/O. The NorthStar CPU
generates mwrite.
Randy
www.s100-manuals.com