Thanks for the info about the ‘oddness’ to both you and another poster I now have some more insight into what I am looking at and for. I probably won’t have a chance to work on it again until tomorrow evening.
I did find a ROM disassembly on Kevin Petit’s folks at the club100 website. Looking at it now whilst minding a little CNC mill making a calibration fixture for a microwave sensor (very slow and boring but it has to be done 😊 ) I’ll do some more investigation and probably be back with more questions. Thanks again everyone! Jeff From: M100 <[email protected]> On Behalf Of Fugu ME100 Sent: Wednesday, May 2, 2018 1:09 AM To: [email protected] Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100 The ‘oddness’ is due to the buffers tri-stating or entering a high-impedance state, as the data-sheet calls it, when ALE goes high. If you put up both the address and ALE trace they should match. If the inputs and outputs of the buffers look good then the next step would to check the address decoders to make sure the ROM, SRAM and IO ports are being selected. The ROM CS should go low immediately after the reset goes high to fetch the 1st instruction from 0000H. For the M100 the first instruction is a JMP 7D33H - the boot routines. There is an M100 ROM disassembly somewhere but I cannot find the link to it at the moment. That I think would help a lot with the debug process. Not sure what type of rosin they used for the soldering process but I have being using 90% CVS isopropyl alcohol to remove it without much problem.
