Could Turbo mode be software selectable? Just curious as if you were to
enter MVT100 (or VT-100 output with CP/M), you wouldn't be constrained
by internal M100 LCD.
Philip
On 2/11/2020 12:44 am, Stephen Adolph wrote:
Final story on 8MHz (well final for now!).
Actually, the processor/ram/keyboard all work at 8MHz. Only one thing
I can see, and it is pretty important, doesn't. The LCD.
The driver chips have to communicate with the CPU, and they are just
too slow to get their data on the bus in time.
So, I think that's the end of the story; no clear way to improve on
the Driver response time.
6.144MHz is exactly 2.5x nominal clock rate. That seems to be achievable.
On Sat, Oct 31, 2020 at 7:12 PM Stephen Adolph <[email protected]
<mailto:[email protected]>> wrote:
On Sat, Oct 31, 2020 at 5:52 PM Joe Grubbs <[email protected]
<mailto:[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....
