GENERAL DESCRIPTIONThe TM8720 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 and LCD driver in a single chip.
FEATURES1. 1.5V operation only and with low power dissipation.
2. Powerful instruction set (86 instructions)
Binary addition, subtraction, BCD adjustment, logical operation in direct.
Single-bit manipulation (set, reset, decision for branch).
Various conditional branches.
16 working registers and manipulation.
LCD driver data transfer.
3. Memory capacity
ROM capacity 1024 x 16 bits.
RAM capacity 64 x 4 bits.
4. Input/output ports
Port IOA 4 pins (with internal pull-low), IOA port has built-in the input signal chattering prevention circuitry.
Port IOB2, 3, 4 3 pins (with internal pull-low), & mask option with BZB, BZ.
5. 4-level subroutine nesting.
6. Interrupt function
One external factor (Pin IOA port).
Two internal factors (Pre-Divider, Timer2).
7. Built-in Alarm, clock or single tone melody generator (BZB, BZ), & mask option with IOB3, 4.
8. One 6-bit programmable timer (Timer 2) with programmable clock source.
9. LCD driver output
12 LCD driver outputs (up to drive 48 LCD segments).
1/4 Duty and 1/2 Bias for LCD display.
Single instruction to turn off all segments.
12 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 oscillators by mask option.
12. HALT function.
13. STOP function.