The MB89640 series has been developed as a general-purpose version of the F2MC*-8L family consisting of proprietary 8-bit, single-chip microcontrollers. In addition to a compact instruction set, the microcontrollers contain a variety of peripheral functions such as dual-clock control system, five operating speed control stages, timers, a PWM timer, serial interface, an A/D converter, a D/A converter, an external interrupt, and a watch prescaler. *: F2MC stands for FUJITSU Flexible Microcontroller.