GENERAL DESCRIPTION
The W742E/C811 (W742C811 is mask type, W742E811 is electrical erasable EPROM type) is a highperformance 4-bit microcontroller (mC) that built in 640-dot LCD driver. The device contains a 4-bit ALU, two 8-bit timers, two dividers in dual-clock operation, a 40 ´ 16 LCD driver, ten 4-bit I/O ports (including 2 output port for LED driving), multiple frequency output, and one channel DTMF generator. There are also eleven interrupt sources and 16-level stack buffer. The W742E/C811 operates on very low current and has three power reduction modes, hold mode, stop mode and slow mode, which help to minimize power dissipation. 

FEATURES
• Operating Voltage
    - 2.4V – 5.5V for mask type
    - 2.4V – 4.8V for electrical erasable EPROM type
• Dual-clock Operation
• Main Oscillator
    - 3.58 MHz or 400 KHz can be selected by code option
    - Crystal or RC oscillator can be selected by code option
• Sub-oscillator
    - Connect to 32.768 KHz crystal only
• Memory
    - 16384(16K) x 16 bit program ROM (including 64K x 4 bit look-up table)
    - 5120(5K) x 4 bit data RAM (including 16 nibbles x 16 pages working registers)
    - 40 x 16 LCD data RAM
• 40 Input/Output Pins
    - Port for input only: 3 ports/12 pins
    - Input/output ports: 3 ports/12 pins
    - High sink current output port for LED driving: 2 port /8 pins
    - DC output port: 2 ports/ 8 pins (selected by code option)
• Power-down Mode
    - Hold mode: no operation (main oscillator and sub-oscillator still operate)
    - Stop mode: no operation (main oscillator and sub-oscillator are stopped)
    - Slow mode: main oscillator is stopped, system is operated by the sub-oscillator (32.768 KHz)
• Eleven Interrupt Sources
    - Four internal interrupts (Divider0, Divider1, Timer 0, Timer 1)
    - Seven external interrupts (RC.0-3, P1.2 (INT0 ), Serial Port, P1.3 (INT1))
• LCD Driver Output
    - 40 segments x 16 commons
    - 1/8 or 1/16 duty (selected by code option) 1/5 bias driving mode
    - Clock source should be the sub-oscillator clock in the dual-clock operation mode
    - 8 level software LCD contrast adjusting
    - LCD operating voltage source could come from VDD or VLCD1 pin input
• MFP Output Pin
    - Output is software controlled to generate modulating or nonmodulating frequency
    - Works as frequency output specified by Timer 1
    - Key tone generator
• DTMF Output pin
    - Output is one channel Dual Tone Multi-Frequency signal for dialling
• 8-bit Serial I/O Interface
    - 8-bit transmit/receive mode by internal or external clock source
• Two Built-in 14-bit Frequency Dividers
    - Divider0: the clock source is the main oscillator (Fosc)
    - Divider1: the clock source is the sub-oscillator (Fs)
• Two Built-in 8-bit Programmable Countdown Tmers
    - Timer 0: one of two internal clock frequencies (FOSC/4 or FOSC/1024) can be selected
    - Timer 1: with auto-reload function and one of two internal clock frequencies (FOSC or FOSC/64 or Fs) can be selected (signal output through MFP pin)
• Built-in 18/15-bit Watchdog Timer Selectable for System Reset, Enable/Disable by Code Option
• Powerful Instruction Set
• 16-level Stack Buffer
• Packaged in 100-pin QFP