GENERAL DESCRIPTION

The TM8724 is an embedded high-performance 4-bit microcomputer with LCD driver. It contains all the necessary functions, such as 4-bit parallel processing ALU, ROM, RAM, I/O ports, timer, clock generator, dual clock operation, LCD driver, look-up table in a single chip. 

BLOCK DIAGRAM

FEATURE

1. 1.5V and 3V operations and with low power dissipation.

2. Powerful instruction set (129 instructions). 

• Binary addition, subtraction, BCD adjust, logical operation in direct and index addressing mode. 

• Single-bit manipulation (set, reset, decision for branch). 

• Various conditional branches. 

• 16 working registers and manipulation. 

• Table look-up. 

• LCD driver data transfer.

3. Memory capacity. 

• ROM capacity 1152 x 16 bits. 

•  RAM capacity 80 x 4 bits.

4. LCD driver output. 

•  5 common outputs and 24 segment outputs (up to drive 120 LCD pixels). 

•  1/1 Duty, 1/2 Duty, 1/3 Duty, 1/4 Duty or 1/5 Duty is selected by MASK option. 

•  1/2 Bias or 1/3 Bias is selected by MASK option. 

•  Single instruction to turn off all segments and coms. 

•  Segment output pins (SEG1~12) could be defined as CMOS or P_open drain output type by mask option.

5. Input/output ports. 

• Port IOA    4 pins, muxed with SEG24~SEG27. 

• Port IOB    4 pins (with internal pull-low), muxed with SEG28~SEG31. 

• Port IOC    4 pins (with internal pull-low), muxed with SEG32~SEG35.

  IOC port had built in the input signal chattering prevention circuitry.

6. 8 level subroutine nesting. 

7. Interrupt function. 

• External factor 2 (INT pin, Port IOC). 

• Internal factors 2 (Pre-Divider, Timer1)

8. Built in Alarm generator. 

• BZB, BZ (Muxed with SEG30, SEG31). 

9. One 6-bit programmable timer with programmable clock source. 

10. Built-in Voltage doubler, tripler charge pump circuit. 

11. Dual clock operation. 

12. HALT function. 

13. STOP function.