Teeprom is for the option rom. FlexROM_100 or FlexROM_102 is the main rom.
Well really just the 100. No one really needs the 102 version because for 102 you can just use a plain 27C256 which is a lot simpler. Just for 102 you want to get some chipquick or fastchip desoldering alloy to get the old rom out without drama or damage. For main rom in a 100, FlexROM_100, http://tandy.wiki/FlexROM_100 or Mike Stein's board. https://oshpark.com/shared_projects/Kil9S1ya If you use flexrom, and you get a soic test clip, the you can re-write the rom after it's soldered. For Mike's board, I don't know, the board itself might serve On Sat, Oct 31, 2020, 7:12 PM Stephen Adolph <[email protected]> wrote: > 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.... > > > > >>
