On Sat, Oct 31, 2020 at 5:52 PM Joe Grubbs <[email protected]> wrote:
> Aww yeah! I'm liking where this is going. Will the sluggish original ROM > handle 8Mhz+? > No, for sure not. Right now I have a 120nsec EEPROM in the socket and it supports 6.2 MHz. If I simply place the original ROM back in - no go. But the Main ROM is the easiest thing to replace. It is already socketed! There are many ways to address it. So far here are the changes to run 6.2 MHz (my current setup) 1) you need a faster CPU + crystal. I'm making a board for that. Which CPU - TBD. There are a few choices. (I really should try the stock CPU and see how fast it really is. I am currently using the 8MHz Tundra 80C85 CPU) 2) you need faster RAM. You could use REXCPM to solve that problem. Otherwise... a lot of soldering work! 3) faster main ROM. Teeprom would be a good solution here. 4) improved M2. stock = TC40H245 (good to 5MHz). I have piggybacked 74HC245 (6MHz) I'm puzzled by what is failing to work at 8.2 MHz. Everything so far looks ok. I'll keep poking around.... >
