The W78C801 is an 8-bit microcontroller with a wide frequency range and low power consumption. The instruction set for the W78C801 is fully compatible with the standard 8051. It includes a 4K bytes Mask ROM, 256 bytes RAM, four 8-bit bi-directional and bit-addressable I/O ports, an additional 6-bit I/O port P4, two 16-bit timer/counters, and a hardware watchdog timer. The microcontroller has two power reduction modes, idle mode and power-down mode, which are software selectable. The idle mode turns off the processor clock but allows for continued peripheral operation. 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 W78C801 is an 8‑bit CMOS microcontroller compatible with the 8051 instruction set. It offers a 4 KB Mask ROM, 256 B RAM, four 8‑bit bi‑directional I/O ports, an additional 6‑bit port (P4), two 16‑bit timer/counters, a watchdog timer and two software‑selectable power‑reduction modes (idle and power‑down). The device operates from DC‑40 MHz and provides 64 KB program and data address spaces.
The document details pin configurations for DIP‑40, PLCC‑44 and PQFP‑44 packages, register maps for interrupt control, watchdog timer, and power management, as well as timing diagrams and mechanical dimensions for each package type.
| Mask ROM | 4 KB |
|---|---|
| RAM | 256 bytes |
| Timer/Counters | Two 16‑bit |
| Watchdog Timer | Present |
| Operating Frequency | DC‑40 MHz |
| Power‑reduction Modes | Idle and Power‑down |
| Program Memory Space | 64 KB |
| Data Memory Space | 64 KB |
The microcontroller 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 crystal oscillator for minimum power consumption.
The W78C801 supports twelve interrupt sources, including external interrupts INT0 through INT9, plus Timer 0 and Timer 1.
Yes, the W78C801 does not contain a serial port.
The device is available in 40‑pin DIP, 44‑pin PLCC and 44‑pin PQFP (44‑pin QFP) packages.