10 May
2010
10 May
'10
11:36 a.m.
Thank you Carl. I did receive a .BIN file of the monitor a while ago
and just recently got it burned into an 8755A. Unfortunately, this has
not fixed the problem-- or, rather, introduced a new problem as the
little machine still does not run at all (frozen or not) with the new
EPROM resident monitor.
So, there is something a little more sinister going on here. Still
investigating...
Assuming you've not made a mistake programming the 8755, and that the
8755 is not defective, have you checked the state of pin 5? It's N/C on
the 8355, and Vpp on the 8755. There's a link on the SDK-85 board
associated with this pin. You might check that.
If you put the original monitor ROM in its socket and put the 8755 in the
ROM extension socket, can you read out the nrwly-programmed EPROM at the
extension ROM location?
-tony