UPD8021 PDF File ( Datasheet )

NEe Microcomputers, Inc. NEe ILPD8021 SINGLE CHIP 8·BIT MICROCOMPUTER DESCRIPTION The NECIlPD8021 is a stand alone 8-bit parallel microcomputer incorporating the following features usually found in external peripherals. The IlPD8021 contains: 1K x 8 bits of mask ROM program memory, 64 x 8 bits of RAM data memory, 21 I, O lines, an B-bit interval timer, event counter, and internal clock circuitry. FEATURES 8-Bit Processor, ROM, RAM, I, O, Timer, Counter Single +5V Supply (+4.5V to +6.5V)