GENERAL DESCRIPTION
The W541E260 is fully compatible with W741E260 in terms of pin assignment and IC function. It is a high-performance 4-bit microcontroller (µC) that provides an LCD driver and the flash EEPROM for the program memory. The device contains a 4-bit ALU, two 8-bit timers, two dividers (for two oscillators) in dual-clock operation, a 32 × 4 LCD driver, and five 4-bit I/O ports (including 1 output port for LED driving). There are also five interrupt sources and a 8-level subroutine nesting for interrupt applications. The W541E260 operates on very low current and has three power reduction modes, hold mode and stop mode in single-clock operation and the dual-clock slow operation, which help to minimize power dissipation.
This chip is available for W541C250 and W541C260 bodies, which can be selected by option code. The W541E260 is suitable for end product manufacturer engineering testing and earlier samples before mass production.

FEATURES
• Operating voltage: 2.4V to 5.5V (LCD drive voltage: 3.0V, or 4.5V)
• Crystal/Ceramic oscillator: up to 4 MHz
• RC oscillator: up to 4 MHz
• Dual-clock operation is selected by code option
• Main oscillator
   − Crystal or RC oscillation circuit can be selected by code option
   − In crystal mode, high-frequency (400 KHz to 4 MHz) or low-frequency (32.768 KHz) oscillation should be selected by code option
   − In RC mode, attention must be paid to the high/low frequency oscillation option, because the LCD driver frequency and the ROM code emulation time are related to this option.
• Sub-oscillator
   − Connect to 32768 Hz crystal only
   − Used in dual-clock operation
• Memory
   − 2048 x 16-bit program flash EEPROM (including 2K x 4-bit look-up table)
   − 128 x 4-bit data RAM (including 16 working registers)
   − 32 x 4 LCD data RAM
• 21 input/output pins
   − Ports for input only: 2 ports/8 pins
   − Input/output ports: 2 ports/8 pins
   − High sink current for LED driving: 1 port/4 pins
   - MFP output pin: 1 pin (MFP)
   - Do not be floating when it is as input or output open-drain (NMOS type).
• Power-down mode
   − Hold function: no operation (excluding main oscillator and sub-oscillator)
   − Stop function: no operation (excluding sub-oscillator)
   − Dual-clock slow operation mode: system is operated by the sub-oscillator (FOSC = Fs and Fm is stopped)
• Five types of interrupts
   − Four internal interrupts (Divider0, Divider1, Timer0, Timer1) for W541C260 body; three internal interrupts (Divider0, Timer0, Timer1) for W541C250 body.
   − One external interrupt (RC Port) for W541C260 body; two external interrupts (RC port and INT pin) for W541C250 body.
• LCD driver output
   − 32 segment x 4 common
   − Static, 1/2 duty (1/2 bias), 1/3 duty (1/2 or 1/3 bias), 1/4 duty (1/3 bias) driving mode can be selected
   − LCD driver output pins can be used as DC output port by code option
   − Clock source can be main oscillator clock in the single-clock operation mode, or sub-oscillator clock in the dual-clock operation mode; operation mode is selected by code option
• MFP output pin
   − Output is software selectable as modulating or non-modulating frequency
   − Works as frequency output specified by Timer 1
• Two built-in 14-bit frequency dividers
   − Divider0: the clock source is the output of the main oscillator
   − Divider1: the clock source is the output of the sub-oscillator
• 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: includes an 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
   − Enable/Disable the watchdog timer can be controlled by command or by option code; the control source (command or option code) can be determined by another option code
• Powerful instruction set: 115 instructions for W541C260 body
                                     119 instructions for W541C250 body
• 8-level subroutine (include interrupt) nesting
• Up to 1 µS instruction cycle (with 4 MHz operating frequency)
• Packaged in 80-pin QFP