Motorola MC14500B

The MC14500B Industrial Control Unit (ICU) is a CMOS one-bit microprocessor designed by Motorola for simple control applications in 1977. It is well-suited to the implementation of ladder logic, and thus could be used to replace relay systems and programmable logic controllers, also intended for serial data manipulation. The processor supports 16 commands, operating at a frequency of 1 MHz. The MC14500B unit does not include a program counter (PC); instead, a clock signal drives a separate PC chip; therefore the size of supported memory is dependent on the implementation of that chip. It was still in production in 1995.

One of the computers known to be based on this processor is the educational WDR 1-bit computer (512 bits of RAM, LED, I/O, keyboard).

The ICU architecture is similar to that of the DEC PDP-14 computer.

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