Overview
The H8/3003 is a microcontroller (MCU) that integrates system supporting functions together with an H8/300H CPU core having an original Hitachi architecture.

The H8/300H CPU has a 32-bit internal architecture with sixteen 16-bit general registers, and a concise, optimized instruction set designed for speed. It can address a 16-Mbyte linear address space. Its instruction set is upward-compatible at the object-code level with the H8/300 CPU, enabling easy porting of software from the H8/300 Series.

The on-chip system supporting functions include RAM, a 16-bit integrated timer unit (ITU), a programmable timing pattern controller (TPC), a watchdog timer (WDT), a serial communication interface (SCI), an A/D converter, I/O ports, a direct memory access controller (DMAC), a refresh controller, and other facilities. Four MCU operating modes offer a choice of data bus width and address space size.