W78C31B is an 8-bit microcontroller produced by Winbond Electronics. It has a working frequency range of DC-40MHz and supports ROMless operation. It has four 8-bit bidirectional parallel ports, two 16-bit timer/counters and a full duplex serial port.
The W78C31B microcontroller offers a wide frequency range, four 8‑bit bidirectional ports, two 16‑bit timer/counters, a full‑duplex serial port and built‑in power‑management modes (idle and power‑down). It supports ROM‑less operation and provides 128 bytes of on‑chip RAM with 64 KB program and data address spaces.
The device is supplied in several packages (DIP‑40, PLCC‑44, QFP‑44, TQFP‑44) and its electrical specifications include a 4.5‑5.5 V operating voltage, up to 40 MHz clock, 70 °C maximum operating temperature and a range of current consumptions for various modes.
| Operating Voltage | 4.5 V – 5.5 V |
|---|---|
| Idle Current | 6 mA (idle mode) |
| Power‑down Current | 50 µA (power‑down mode) |
| Maximum Clock Frequency | 40 MHz |
| RAM | 128 bytes |
| Program Memory | 64 KB |
| Data Memory | 64 KB |
| I/O Ports | Four 8‑bit bidirectional ports |
| Operating Temperature | 0 °C to 70 °C |
| Storage Temperature | -55 °C to +150 °C |
| Package Options | DIP‑40, PLCC‑44, QFP‑44, TQFP‑44 |
It provides two software‑selectable power‑reduction modes: idle mode, which stops the processor clock while keeping peripherals active, and power‑down mode, which stops the oscillator for minimum consumption.
The device contains four 8‑bit bidirectional parallel ports.
The microcontroller can operate up to 40 MHz.
It is available in DIP‑40, PLCC‑44, QFP‑44 and TQFP‑44 packages.