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 and watchdog timer in a single chip.
features
1. 1.5v and 3v operations and with low power dissipation.
2. powerful instruction set (129 instructions).
* 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.