W78E51C is an 8-bit microcontroller which can accommodate a wider frequency range with low power consumption. The instruction set for the W78E51C is fully compatible with the standard 8051. The W78E51C contains many enhanced functions, such as new defined peripheral, reduced EMI emission, more flexible lock and MOVC inhibit, higher security and faster clock speed.
The W78E51C is an 8‑bit CMOS microcontroller with a 4 KB Flash EPROM, 128 bytes of RAM, four 8‑bit bi‑directional I/O ports, an additional 4‑bit port, two 16‑bit timers, a full‑duplex UART and a watchdog timer. It operates from a wide supply voltage of 4.5 V to 5.5 V and supports both idle and power‑down power‑saving modes.
The datasheet provides detailed pin configurations, functional block diagrams, electrical characteristics, timing waveforms, typical application circuits and package dimensions for DIP‑40, PLCC‑44 and PQFP‑44 variants.
| Flash memory | 4 KB on‑chip |
|---|---|
| RAM | 128 bytes |
| Supply voltage | 4.5 V to 5.5 V |
| I/O ports | Four 8‑bit ports + one 4‑bit port |
| Additional I/O port | One extra 4‑bit bit‑addressable port |
| Timers | Two 16‑bit timer/counters |
| Serial interface | One full‑duplex UART |
| Watchdog | Integrated watchdog timer |
| Program memory space | 64 KB |
| Data memory space | 64 KB |
| Interrupt sources | Seven sources, two‑level priority |
The device operates from 4.5 V to 5.5 V.
It has four 8‑bit bi‑directional ports plus an extra 4‑bit bit‑addressable port.
The microcontroller supports seven interrupt sources with two‑level priority.