The mPD784021 is a product of the m PD784026 sub-series in the 78K/IV series. It contains various peripheral hardware such as RAM, I/O ports, 8-bit resolution A/D and D/A converters, timers, serial interface, and interrupt functions, as well as a high-speed, high-performance CPU. The m PD784021 is a ROM-less product of the m PD784025 or mPD784026. The mPD784020 differs from the mPD784021 only in its RAM size: 512 bytes are allocated for the mPD784020, while 2048 bytes are allocated for the mPD784021. For specific functions and other detailed information, consult the following user's manual. This manual is required reading for design work. mPD784026 Sub-Series User's Manual, Hardware : U10898E