Micro Professor I/O memory by Lee Davison
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This is the I/O memory board that went with the Micro Professor. It provides the MPF1 with paralell I/O using a Z80 PIO chip, serial I/O with an 8251 UART, 4k ROM expansion with a 2732 EPROM and 6k RAM expansion with three 2116 2k RAM chips.

The board shown has had the three 2k RAMs replaced with battery backed RAM and the EPROM has been replaced by an 8k RAM giving 14k total on this board.

Also, as with the EPROM programmer, the inductor for the onboard +12v/-10v generator has been replaced with a larger value so that the switcher chip runs cool.

So far all that is present are the diagrams.

View the circuit, sheet 1 of 3.

View the circuit, sheet 2 of 3.

View the circuit, sheet 3 of 3.

Download all the diagrams in one zip file.

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