W78  -  Series DataSheet
W78ERD2  -  8-bit microcontroller which is pin- and instruction-set-compatible with the standard 80C52  -  Nuvoton Technology Corporation  -  8051

Description
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 in-system 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, bi-directional 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.
Features
8-bit CMOS microcontroller
Pin-compatible with standard 80C52
Instruction-set compatible with 80C52
Four 8-bit I/O ports; Port 0 has internal pull-up resisters enabled by software.
One extra 4-bit I/O port with interrupt and chip-select functions
Three 16-bit timers
Programmable clock out
Programmable Counter Array (PCA) with PWM, Capture, Compare and Watchdog functions
9 interrupt sources with 4 levels of priority
Full-duplex serial port with framing-error detection and automatic address recognition
64-KB, in-system-programmable, Flash EPROM (AP Flash EPRAOM)
4-KB auxiliary Flash EPROM for loader program (LD Flash EPROM)
256-byte on-chip RAM
1-KB auxiliary RAM, software-selectable
Software Reset
12 clocks per machine cycle operation (default). Speed up to 40 MHz.
6 clocks per machine cycle operation set by the writer. Speed up to 20 MHz.
2 DPTR registers
Low EMI (inhibit ALE)
Built-in power management with idle mode and power down mode
Code protection