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Data Sheet

User manual


UM-4BIT Series Difference List_EV10.pdf



Development Documnets
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Development Tools

The TM8957 is an embedded high-performance 4-bit microcontroller with LCD 
driver on a chip. 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 etc. on a 
signal chip.

1. Low power dissipation. 
 1.5V/3V operating voltage range. 
2. Powerful instruction set. 
 Binary addition, subtraction, BCD adjustment. BCD can be performed 
  directly in addition/ subtraction operations. 
 4 bits x 4 bits Multiplier 
 Single-bit manipulation (set, reset, decision for branch). 
 Various conditional branches. 
 16 initial working registers and manipulators. (can be extended to all RAM 
  with Page Mode) 
 Look-up Table. 
 LCD driver data transfer. 
3. ROM Capacity. 24K x 16 bits. 
 Instruction ROM Max. Capacity 24K x 16 bits. 
 Table ROM Max. Capacity 32K / 16K x 8 / 16 bits. 
4. RAM Capacity. 6K / 3K / 1.5K x 4 / 8 / 16 bits. 
 LCD Max. Capacity 256 / 128 / 64 x 4 / 8 / 16 bits. 
 STACK Max. Capacity 16 x 16 bits. 
 HL/ZR store Max. Capacity 16 / 16 x 16 bits. 
5. With direct/index addressing mode in data RAM access. 
6. LCD driver output. 
 16common outputs and 64 segment outputs. 
 1/4 ~ 1/16 Duty can be selected by mask option. 
 1/3 ~ 1/5 Bias can be selected by mask option. 
 Single instruction to turn off all segments. 
 COM5 ~ 16 can be defined as CMOS or P_open drain type output port by 
  mask option. 
 External regulator mode for VL1/2 by mask option. 
7. Input/output ports. 
 Port IOA 4 pins (with internal pull-low, input signal chattering prevention 
  circuitry), and can be defined as CX and RFC0 ~ 2 by mask option. 
 Port IOB 4 pins (with internal pull-low), and can be defined as ELC, ELP, 
  BZB, BZ by mask option. 
 Port IOC 4 pins (with internal pull-low, low-level-hold, input signal 
  chattering prevention circuitry). 
 Port IOD 4 pins (with internal pull-low, input signal chattering prevention 
  circuitry), and can be defined as SEG61~64 by mask option. 
 Port IOE 4 pins (with internal pull-low), and can be defined as RFC3 ~ 5 
  and CX2 by mask option. 
8. Interrupt function. 
 External factors 5 (INT pin, Port IOA, IOC, IOD & KI input). 
 Internal factors 5 (Pre-Divider, Timer1, Timer2, Timer3 & RFC). 
9. Built-in EL-light driver. 
 ELC, ELP. Can be defined as IOB1 and IOB2 by mask option. 
10. Built-in Alarm, clock or single tone melody generator. 
 BZB, BZ. Can be defined as IOB3 and IOB4 by mask option. 
11. Built-in resistance to frequency converter. 
 CX, RFC0 ~ 5 CX2,. Can be defined as IOA1 ~ 4 and IOE1 ~ 4 by mask 
12. Built-in key matrix scanning function. 
 KO1 ~ KO16 (Shared with SEG1 ~ 16) 
 KI1 ~ KI4 (Can be defined as IOB1 ~ 4 by mask option) 
13. Three 6-bit programmable timer with programmable clock source. 
 Read the content at any time 
 Merge 2 or 3 timers into one 12-bit or 18-bit timer. 
 Used as a counter for RFC 
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 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. 
Timer / Calendar / Calculator / Thermometer 

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