The LC665304A, LC665306A, LC665308A, LC665312A, and LC665316A are 4-bit CMOS microcontrollers that integrate on a single chip all the functions required in a system controller, including ROM, RAM, I/O ports, a serial interface, 16-value comparator inputs, timers, interrupt functions, and an optional sub-oscillator circuit. These microcontrollers are available in a 48-pin package.