TM8721
GENERAL DESCRIPTION
The TM8721 is an embedded high-performance 4-bit microcomputer with LCD driver. It contains all theof the following functions in a single chp: 4-bit parallel processing ALU, ROM, RAM, I/O ports, timer.clock generator, dual clock operation, Resistance to Frequency Converter (RFC), LCD driver, look-uptable.
BLOCK DIAGRAM
FEATURE
1. Powerful instruction set (137 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.
Look-up table.
LCD driver data transfer.
2. Memory capacity
ROM capacity 1024 x 16 bits.
RAM capacity 64 x 4 bits.
3. Input/output ports
Port IOA4 1 pin (with internal pull-low).
IOA4 port had built in the input signal chattering prevention circuitry.
Port IOC 4 pins (with internal pull-low, low-level-hold).
Port IOB3,4 2 pins (with internal pull-low), & mask option with BZB, BZ.
4. 8 level subroutine nesting.
5. Interrupt function
External factor 1 (Pin IOA4 port).
Internal factors 3 (Pre-Divider, Timer2 & RFC).
6. Built in Alarm, clock or single tone melody generator (BZB, BZ), & mask option with IOB3, 4.
7. Built-in R to F Converter circuit
CX, RR, RT.
8. One 6-bit programmable timer (Timer 2) with programmable clock source.
9. LCD driver output
9 LCD driver outputs. (Up to drive 36 LCD segments)
1/4 Duty and 1/2 Bias for LCD display.
Single instruction to turn off all segments.
9 DC/Open Drain outputs for LED mask option.
16 LCD Address.
10. Built-in Voltage double charge pump circuit.
11. Clock oscillation can be defined as X’tal, external-R or internal-R 2 type oscillator by mask option.
12. HALT function.
13. STOP function.
