GENERAL DESCRIPTION
The W742E/C816 [W742E 816 is EEPROM type, W742C816 is mask type] is a high-performance 4-bit microcontroller (µC) 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, one channel DTMF generator and FSK modulator of CCITT V.23 or Bellcore 202. There are also eleven interrupt sources and 16-level stack buffer. The W742E/C816 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 - 6.0V for mask type
    − 2.4V - 4.8V for EEPROM 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
    − 32768(32K) 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 non-modulating 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 dialing (Continue ...)