The MB91110 series is a standard single-chip micro controller featuring various I/O resources and bus control mechanisms to incorporate the control with required for high performance high-speed CPU processes, having a 32-bit RISC CPU (FR30 series) in its core. Although external bus access is the basis for supporting a large address space accessible by a 32-bit CPU, a 1-KB instruction cache memory has been built-in to increase the instruction/ execution speed of the CPU.