Preliminary W741C20X
GENERAL DESCRIPTION
The W741C20X is a high-performance 4-bit microcontroller (µC) that operates on very low current.
The device contains a 4-bit ALU, two 8-bit timers, a divider, a serial port, and five 4-bit I/O ports
(including 3 output ports for LED driving). There are also seven interrupt sources and 8-level
subroutine nesting for interrupt applications. The W741C20X has two power reduction modes, hold
mode and stop mode, which help to minimize power dissipation.
The W741C20X is suitable for remote controllers, toy controllers, keyboard controllers, speech
synthesis LSI controllers, and other products.
FEATURES
• Operating voltage: 2.2V to 5.5V
• Crystal or RC oscillation circuit can be selected by the code option
− Crystal/Ceramic oscillator: up to 4 MHz
− RC oscillator: up to 4 MHz
• Both in crystal or RC oscillator operation mode, high-frequency (400 KHz to 4 MHz) or low-
frequency (32.768 KHz) oscillation must be determined by the code option
• Memory
− 2048 x 16 bit program ROM (including 2K x 4 bit look-up table)
− 128 x 4 bit data RAM (including 16 working registers)
• 21 input/output pins
− Input/output ports: 4 ports/16 pins
− Serial input/output port: 1 port /4 pins (high sink current for LED driving)
− MFP output pin: 1 pin (MFP)
• Power-down mode
− Hold function: no operation (except for oscillator)
− Stop function: no operation (including oscillator)
• Seven types of interrupts
− Five internal interrupts (Divider 0, Timer 0, Timer 1, and Serial I/O)
− Two external interrupts (Port RC and INT pin)
• MFP output pin
− Output is software selectable as modulating or nonmodulating frequency
− Works as frequency output specified by Timer 1
• Built-in 14-bit clock frequency divider circuit
• Two built-in 8-bit programmable countdown timers
− Timer 0: One of two internal clock frequencies (FOSC/4 or FOSC/1024) can be selected
− Timer 1: Offers auto-reload function, and one of two internal clock frequencies (FOSC or
FOSC/64) can be selected, or falling edge of pin RC.0 can be selected (output through MFP pin)
• Built-in 18/14-bit watchdog timer selectable for system reset
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