Some kind of borked re-send of a draft. Didn't I already send a proper version of that?
Anyway disregard the last bit. I was starting to wonder if Mike's board might work as it's own programming adapter because it includes both the old and new pinouts. But that was silly and won't work because you can't install both sets of pins at the same time. On Sun, Nov 1, 2020, 11:44 AM Brian White <[email protected]> wrote: > 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.... >> >> >> >> >>>
