W78ERD2

The W78ERD2 is an 8-bit microcontroller which is pin- and instruction-set-compatible with the standard 80C52. The W78ERD2 contains a 64-KB Flash EPROM whose contents may be updated insystem by a loader program stored in an auxiliary, 4-KB Flash EPROM. Once the contents are confirmed, it can be protected for security.

The W78ERD2 also contains 256 bytes of on-chip RAM; 1 KB of auxiliary RAM; four 8-bit, bidirectional and bit-addressable I/O ports; an additional 4-bit port P4; three 16-bit timer/counters; and a serial port. These peripherals are all supported by nine interrupt sources with 4 levels of priority.

The W78ERD2 has two power-reduction modes: idle mode and power-down mode, both of which are software-selectable. Idle mode turns off the processor clock but allows peripherals to continue operating, while power-down mode stops the crystal oscillator for minimum power consumption. Power-down mode can be activated at any time and in any state without affecting the processor.