The W78C51C microcontroller is an 8-bit microcontroller that offers a wider frequency range compared to most 8-bit microcontrollers on the market. It is compatible with the industry standard 80C51 microcontroller series. The microcontroller features four 8-bit bidirectional parallel ports, two 16-bit timer/counters, and a serial port. These peripherals are supported by a five-source, two-level interrupt capability. It has 128 bytes of RAM and a 4K byte mask ROM for application programs. The W78C51C microcontroller also has two power reduction modes, idle mode and power-down mode, which can be selected through software. The idle mode turns off the processor clock while allowing peripheral operation, and the power-down mode stops the crystal oscillator for minimal power consumption. The external clock can be stopped at any time and in any state without affecting the processor.
The W78C51C is an 8‑bit CMOS microcontroller compatible with the 80C51 family. It features four 8‑bit bidirectional ports, two 16‑bit timer/counters, a full‑duplex serial port, 128 bytes of RAM, and 4 KB of mask ROM, supporting a 64 KB program and data address space.
The document includes pin‑out tables, functional block descriptions, absolute maximum ratings, DC and AC electrical characteristics, timing diagrams, and detailed package dimensions for DIP, PLCC, QFP and TQFP variants.
| Operating Voltage (VbD) | 4.5 V – 5.5 V |
|---|---|
| Operating Temperature (TA) | 0 °C – 70 °C |
| Storage Temperature (TST) | -55 °C – +150 °C |
| Operating Current (IDD, no load) | 30 mA at VDD = 5.5 V |
| Idle Current (IIDLE) | 6 mA at VDD = 5.5 V |
| Maximum Clock Frequency | 40 MHz |
| On‑chip RAM | 128 bytes |
| On‑chip Mask ROM | 4 KB |
The device operates from 4.5 V to 5.5 V.
It provides four 8‑bit bidirectional parallel ports.
The microcontroller includes two 16‑bit timer/counters.
The W78C51C can operate up to 40 MHz.