The MC14500B Industrial Control Unit (ICU) is a singlebit CMOS processor. The ICU is designed for use in systems requiring decisions based on successive singlebit information. An external ROM stores the control program. With a program counter (and output latches and input multiplexers, if required) the ICU in a system forms a storedprogram controller that replaces combinatorial logic. Applications include relay logic processing, serial data manipulation and control. The ICU also may control an MPU or be controlled by an MPU.