PolyMorphic Systems - 8080 CPU
This was the only CPU board Polymorphic
Systems made. That said, it was a very advanced board at the time it
The board had space for 3.5K of onboard RAM and ROM. This
memory occupies a contiguous block of 4K and could via jumpers be placed at
0,8000H or E000H. Space for 3 2708 EPROMS were on the board. The ROM's occupy
the first 3K of the 4K space. There was one 512 RAM chip on the board as well.
A Real Time Clock was obtained by processing the 50/60 Hz power line ripple.
The white chip (not the CPU), was the famous "4.0 Monitor" ROM which had a
simulated front panel, and allowed single-stepping of assembly language
programs. It could also load and store programs on cassette tape through a
separate interface. This was the only ROM installed on the original
Poly-88. The other two ROMs, including the one marked V.75 (below),
were added to support floppy disks.
Two sockets at the upper right could be connected to "serial mini-cards" driven
by the 8251 UART on the CPU card. Only one of the two cards could be in
use at any time. One could be configured for audio in/out and was
connected to a cassette tape recorder for program storage. The other
provided RS232 signals to a serial printer, which was the most common kind of
printer before the IBM-PC made a parallel Centronics interface their standard.
The manual for this board (along with
info about other boards in the Poly-88) can be obtained
There was a later mod to modify the SM1 and Wait S-100 signals.
This can be obtained
There was a small add-on card that was sometimes attached to the Poly-88 CPU card
that had to do I think with processing interrupts. It is shown above. Would
welcome comments on this.
Other PolyMorphic Systems S-100 Boards
8080 CPU FDC
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