W78E51B

The W78E51B is an 8-bit microcontroller which can accommodate a wider frequency range with low power consumption. The instruction set for the W78E51B is fully compatible with the standard 8051.

The W78E51B contains an 4K bytes MTP ROM (Multiple-Time Programmable ROM); a 128 bytes RAM; four 8-bit bi-directional and bit-addressable I/O ports; an additional 4-bit I/O port P4; two 16-bit timer/counters; a hardware watchdog timer and a serial port. These peripherals are supported by seven sources two-level interrupt capability. To facilitate programming and verification, the MTPROM inside the W78E51B allows the program memory to be programmed and read electronically. Once the code is confirmed, the user can protect the code for security.

The W78E51B microcontroller has two power reduction modes, idle mode and power-down mode, both of 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.