while stewing over how to speed up the data bus, I had the idea to piggy back 2 74HC245 bi-di drivers.The nice thing about this hack is that you can just solder on another part... easy. This combination is the fastest, and still low power! In this config I can run at *6MHz*, but the LCD starts to show errors, and serial quits working. (also, I am using REXCPM, which has faster system RAM). So 6MHz seems like a step too far.
Practical outcomes: There are 2 good configs 5MHz: needs Fast CPU, and REXCPM 4MHz: needs Fast CPU 6.2MHz 4.94MHz 4.11MHz 6MHz, screen errors, communication errors works well works well 81c55 stock stock stock 80c85 8mhz 5mhz 5mhz ram Rexcpm Rexcpm stock M2 buffer piggy back stock stock On Thu, Oct 29, 2020 at 8:31 PM Stephen Adolph <[email protected]> wrote: > Well, it is quite noticeable, still an M100 though. I would say the > responsiveness is good. > Harder on the batteries though. > Since I use M100 virtually always on external power, a turbo machine > could be ok. > > I'm going to try and get the fastest M2 replacement I can, and see if it > can be pushed further. > > "74VHC245" > > > > On Thu, Oct 29, 2020 at 7:12 PM Joshua O'Keefe <[email protected]> > wrote: > >> On Oct 29, 2020, at 3:12 PM, Stephen Adolph <[email protected]> wrote: >> >> update for the hardware geeks (I may be the only one?) >> >> >> My education was on the hardware side of things, though I've never put it >> into practice. It is interesting to hear your regular reports of your >> various experiments. Please keep it up! >> >> Swapping M2 for a faster 74LS245 yields *5MHz.* >> >> >> That is incredible. Does the corresponding (presumed) improvement in LCD >> performance give a feel of speed boost? >> >
