The APU429 is an embedded high performance 4-bit micro-computer with an on-chip LCD driver. It contains all the necessary functions in a single chip: 4-bit parallel processing ALU, ROM, RAM, I/O ports, timer, clock generator, dual clock, RFC, EL-light, LCD driver, look-up table, watchdog timer and keyboard scanning. The instruction set includes not only 4-bit operation and manipulation instructions but also various conditional branch instructions and