The H8/300L Series is a series of single-chip microcomputers (MCU: microcomputer unit), built around the high-speed H8/300L CPU and equipped with peripheral system functions on-chip. Within the H8/300L Series, the H8/3644 Group of microcomputers are equipped with a UART (Universal Asynchronous Receiver/Transmitter). Other on-chip peripheral functions include five timers, a 14-bit pulse width modulator (PWM), two serial communication interface channels, and
an A/D converter, providing an ideal configuration as a microcomputer for embedding in high level control systems. In addition to the mask ROM version, the H8/3644 is also available in a ZTAT™ version with on-chip user-programmable PROM, and an F-ZTAT™ version with on chip flash memory that can be programmed on-board. Table 1 summarizes the features of the H8/3644 Group.