The PD30121 (VR4121) is one of NEC's VR SeriesTM RISC (Reduced Instruction Set Computer) microprocessors and is a high-performance 64-/32-bit microprocessor employing the MIPS TM RISC architecture. The VR4121 uses the high-performance, super power-saving VR4120TM as the CPU core, and has many peripheral functions such as a DMA controller, software modem interface, serial interface, keyboard interface, IrDA interface, touch panel interface, real-time clock, A/D converter, and D/A converter. Configured with these functions, the VR4121 is suitable for high-speed battery-driven portable information systems. The external memory bus width can be selected from 32 bits and 16 bits, realizing high-speed data transfer. Detailed function descriptions are provided in the following user's manual. Be sure to read it before designing.