[sebhc] New CPU card

Lee Hart leeahart at earthlink.net
Sun Jun 13 15:16:43 CDT 2004

Carroll Waddell wrote:
> As soon as I get my H8 up and everything working correctly, I thought
> about building a new CPU card. Based on Pat Swayne's Z80 upgrade
> article, how about a new board with a Z80 processor, 64K RAM, and the
> extended configuration (the little board in P10) all on one card?
> Anyone interested?

Yes! In fact, I was thinking of something similar. My thought was to put
the Z80 and 64k of memory on the front panel board! Thus, *no* bus slots
would be taken up for CPU or memory.

We could also eliminate the discrete wiring between front panel and
motherboard. The thought is that such a board could be the basis of a
kit to get *new* people interested in the H8. They could build just the
front panel+Z80+memory and have a working single-board computer. Add the
motherboard and accessory boards to expand it into a "real" system.

The other advantage to this (for present H8 owners) is that the bus can
stay at 2 MHz, while all Z80-memory accesses can run at a much higher
speed (8 MHz Z80s are essentially the same price as 2.5 MHz parts). For
legacy support, we could even have a way to select CPUs, so you could
even leave the old 8080 and memory cards in the system and run them.
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
Lee A. Hart  814 8th Ave N  Sartell MN 56377  leeahart_at_earthlink.net

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