Bonjour, Cedric,
If possible, I would try to get a chip from a different manufacturer.
Even during normal programming people have found subtle differences among
brands in the behaviour of some pins, especially /PGM (pin 27 in this case),
and since this is a non-standard undefined use it's possible that what works
with one will be unreliable with another.
Maybe also try to find a 120ns -12 version while you're at it.
m
----- Original Message -----
From: Cedric Amand
To: m...@bitchin100.com
Sent: Saturday, November 19, 2022 6:56 AM
Subject: Re: [M100] custom key mapping generator for Tandy 200
Currently, I've been trying to replace my main 32KB ROM with a ST M27C256A-100
This works.
And I've been trying to replace the 8KB with a ST M27C64A-150
This does not work for me. The system freezes after seconds, then becomes
completely unusable to the point even the power button (or a hard reset) does
nothing, screen displays garbage or just all black pixels
I've ordered alternative parts, in case my 27C64 is marginal in some way, but
the ROM reads and re-reads fine in a TL866, and it's a copy of the original ROM.
I'm continuing my experiments when new parts arrive.
Le 2022-11-19 01:19, Stephen Adolph <twospru...@gmail.com> a écrit :
So, to recap,
1. We have a spreadsheet to create custom key maps for Tandy 200
2. Separately, we are trying to confirm in hardware that a single 27C64
rom can be substituted for M13, to implement the custom keymap.
I would encourage the approach for dealing with different keyboards on
other machines.
Keep in mind.. if the actual characters themselves change, the modification
is deeper. Such is the case for M10 for example. (Or just use the usa
character set to make it easy).
Thanks
Steve
