[Coco] [Color Computer] POKE 65495,0

[James Diffendaffer]

I think the easiest way to make the highest speed poke work
consistently would be to create an interrupt routine that would load
from a different RAM address every few interrupts.  The address would
change after each load so each column of RAM would be refreshed at
least once in a 4 second interval.  At least that's about what my CoCo
1 could manage in that mode.

A better alternative would be to replace the SAM with a PLD and SDRAM
making refreshes obsolete.  It would also open up a few possibilities
such as even higher CPU clock rates by changing the divisor to 1, 2 or
4 instead of 8 or 16.  It would require a different CPU but we already
know there are CPUs that handle 4MHz.  The PLD could also use the
burst mode of the SDRAM to pre-load data for the VDG 4 bytes at a time
to reduce it's use of the buss.