TM8725
GENERAL DESCRIPTION
The TM8725 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, Resistance to Frequency Converter(RFC), EL panel driver, LCD driver, look-up table, watchdog timer and key matrix scanning circuitry in a single chip.
BLOCK DIAGRAM
FEATURE
1.Low power dissipation
2.Powerful instruction set (178 instructions).
Binary addition, subtraction, BCD adjust, logical operation in direct and index addressing mode.
Single-bit manipulation (set, reset, decision for branch).
Various conditional branch.
16 working registers and manipulation.
Table look-up.
LCD driver data transfer.
3.Memory capacity
ROM capacity3072x 16 bits.
RAM capacity384x 4 bits.
4.LCD driver output
6 common outputs and 40 segment outputs (up to drive 240 LCD segments).
1/2 Duty, 1/3 Duty, 1/4 Duty, 1/5 Duty or 1/6Duty is selected by MASK option.
1/2 Bias or 1/3 Bias is selected by MASK option.
Single instruction to turn off all segments.
COM5~6, SEG1~40 could be defined as CMOS or P_open drain type output by mask option.
5.Input/output ports
Port IOA4 pins (with internal pull-low), muxed with SEG24~SEG27.
Port IOB4 pins (with internal pull-low). muxed with SEG28~SEG31
Port IOC4 pins (with internal pull-low, low-level-hold), muxed with SEG32~SEG35. IOC port had built in the input signal chattering prevention circuitry.
Port IOD4 pins (with internal pull-low), muxed with SEG36~SEG39. IOD port had built in the input signal chattering prevention circuitry.
6.8 level subroutine nesting.
7.Interrupt function.
External factors4(INT pin, Port IOC, IOD & KI input).
Internal factors4(Pre-Divider, Timer1, Timer2 & RFC).
8.Built-in EL-light driver
ELC, ELP (Muxed with SEG28, SEG29).
9.Built in Alarm, clock or single tone melody generator
BZB, BZ (Muxed with SEG30, SEG31).
10.Built-in resistance to frequency converter
CX, RR, RT, RH (Muxed with SEG24 ~ SEG27)
11.Built in key matrix scanning function
K1~K16 (Shared with SEG1~SEG16).
12.KI1~KI4 (Muxed with SEG32 ~ SEG35)
13.Two 6-bit programmable timer with programmable clock source.
14.Watch dog timer.
15.Built-in Voltage doubler, halver, tripler charge pump circuit.
16.Dual clock operation
slow clock oscillation can be defined as X’tal or external RC type oscillator by mask option.
fast clock oscillation can be defined as 3.58MHz ceramic resonator, internal R or external R type oscillator by mask option.
17.HALT function.
18.STOP function.
