GENERAL DESCRIPTION

The TM87M23 is a Multiple Time Programmed ROM embedded high-performance 4-bit microcomputerwith LCD driver. It contains all the necessary functions, such as 4-bit parallel processing ALU. ROMRAM, I/0 ports, timer, clock generator, dual clock operation, Resistance to Frequency Converter (RFC).EL panel driver, LCD driver, look-up table, watchdog timer and key matrix scanning circuitry in a signalchip.

BLOCK DIAGRAM

FEATURE

1.Low power dissipation.

• 1.5V/3V operating voltage range.

2.Powerful instruction set.

• Binary addition, subtraction, BCD. BCD can be executed directly in addition, subtraction.

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

• Various conditional branches.

• 16 initial working registers and manipulators.

• Table look-up.

• LCD driver data transfer.

3.ROM(MTP) capacity   1.5K x 16 bits

• Instruction ROM Max. capacity   1.5K x 16 bits

• Table ROM Max. capacity   2816x 8 bits.

• Endurance: 1000 cycles (min.)

4.RAM capacity   96x 4bits (Address 50h - 6Fh is no use)

5.With direct/index addressing mode in data RAM access.

6.LCD driver output.

• Max 135 LCD dots by 5 common outputs and 27 segment outputs.

• SEG24-35 can be defined as IOA1-4/CX, RR,RT,RH,IOB1-4/ELC,ELPBZB.BZIOC/KI1-4 by option.

• 1/1-1/5 Duty can be selected by option.

• 1/2 ~1/3 Bias can be selected by option.

• Single instruction to turn off all segments.

• COM1-5. SEGl-1221-35 can be defined as CMOS or P open drain type output byoption(COMl & SEG35 force same PSTB & DBUS option for CMOS or P open drain typeoutput).

7.Input/output ports

• Port IOA4 pins (with internal pull-low), and can be defined as SEG24-27/CXRRRTRH byoption.

• Port IOB4 pins (with internal pull-low), and can be defined as SEG28-31/ELC, ELP, BZB, BZ byoption.

• Port IOC4 pins (with internal pull-low, low-level-hold, input signal chattering preventioncircuitry), and can be defined as SEG32-35/KIl-4 by option.

8.Interrupt function.

• External factors   3 (INT pin, Port OC & KI input).

• Internal factors   4 (Pre-Divider. Timerl Timer2 & RFC)

9.Built-in El-light driver.

• ELC，ELP. Can be defined as SEG28, 29/10B1, 2 by option.

10. Built-in Alarm, clock or single tone melody generator.

• BZB. Bz. Can be defined as SEG30. 31/1OB3, 4 by option.

11. Built-in resistance to frequency converter.

• CX, RR, RI, RH. Can be defined as SEG24-27/IOA1-4 by option.

12. Built-in key matrix scanning function.

• KO1-KO16(Shared with SEGl-16)

• KIl-K14.Can be defined as SEG32-35/10C1-4 by option.

13. Two 6-bit programmable timers with programmable clock source. 

• Read out the content in anytime

14. Watchdog timer.

15. Built-in voltage charge halver & pump circuit

16. Dual clock operation

•  slow clock oscillation can be defined as X'tal or external RC type oscillator by option.

• fast clock oscillation can be defined as internal R or external R(Fast Only) type oscillator byoption.

17. HALT function.

18. STOP function.

19. Built-in Low Voltage Reset