The W78L51 microcontroller is an 8-bit microcontroller with a wider frequency and supply voltage 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, one extra 4-bit bit-addressable I/O port, two additional external interrupts, two 16-bit timer/counters, one watchdog timer, and a serial port. These peripherals are supported by a seven-source, two-level interrupt capability. The microcontroller has 128 bytes of RAM and 4K bytes of mask ROM for application programs. It also offers two power reduction modes: idle mode and power-down mode, which can be selected via software. The idle mode turns off the processor clock while allowing peripheral operation, and the power-down mode stops the crystal oscillator for minimum power consumption. The external clock can be stopped at any time and in any state without affecting the processor.
The Winbond W78L51 is an 8‑bit microcontroller that offers a wide supply voltage range, DC‑24 MHz operation, and compatibility with the standard 80C51 series. It includes four 8‑bit bidirectional ports, an extra 4‑bit port, two 16‑bit timer/counters, a full‑duplex serial port, and a watchdog timer.
The document provides a detailed description of pins, functional blocks, power‑reduction modes, EMI reduction features, and package dimensions for DIP‑40, PLCC‑44, and QFP‑44 variants.
| Supply voltage | 1.8 V to 5.5 V |
|---|---|
| Maximum clock frequency | DC‑24 MHz |
| On‑chip RAM | 128 bytes |
| On‑chip ROM | 4 KB mask ROM |
| Program memory address space | 64 KB |
| Data memory address space | 64 KB |
| I/O ports | Four 8‑bit bidirectional ports |
| Extra I/O port | One 4‑bit bit‑addressable port (P4) |
| Timer/counters | Two 16‑bit |
| Serial port | One full‑duplex |
| Interrupt capability | Seven‑source, two‑level |
| Power‑reduction modes | Idle mode and power‑down mode |
| Package options | DIP‑40, PLCC‑44, QFP‑44 |
The W78L51 operates from 1.8 V up to 5.5 V.
It provides four 8‑bit bidirectional ports plus an extra 4‑bit bit‑addressable port (P4).
The microcontroller has two power‑reduction modes: idle mode and power‑down mode.
The device can run at up to DC‑24 MHz.