Cromemco Z80 ZPU
This was the workhorse Cromemco CPU
board for many years. While it was clearly pre-IEEE-696 it was very reliable and
The board had power-on-jump circuitry to
one of 16 memory locations using the switch settings on the left hand side.
Special at the time when it first came out the board could be switched from 2 to
4MHz by the switch up near the power regulator. It also had the capability to
insert 1 to 3 wait states to accommodate slower memories. Like the Vector
Graphic Z80 board it also put the Z80 refresh signal on the bus (pin 66).
However Cromemco never did utilize this signal on their dynamic RAM boards.
One small point of note. The pin-out for
the Altair/IMSAI front panel connector at the top right of the board has the
data lines going D7 to D0 not the scrambled way Altair had.
The manual can be obtained
Other Cromemco S-100
4FDC 16FDC 64FDC
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