The MB91121 is a microcontroller with a 32-bit RISC CPU (FR family *) as the core, incorporating a variety of I/O resources, a bus control facility, and a multiplier-accumulator (simplified DSP) with internal program RAM for built-in control applications which require advanced, high-speed CPU processing. While being based on external bus access for supporting a vast address space accessed by the 32-bit CPU, it contains 1 K bytes of instruction cache memory and 4 K bytes of RAM (8 K bytes when the DSP is not used) for speeding up the execution of instructions by the CPU. In this way, the device is designed for built-in applications which require high performance and processing power of the CPU, such as digital camera, navigation system, and high-performance FAX, and printer controls. * : FR Family stands for FUJITSU RISC controller.