INTRODUCTION
The ST7546T is a driver & controller LSI for graphic dot-matrix liquid crystal display systems. It contains 102 segment and 65 common with 1 ICON driver circuits. This chip is connected directly to a microprocessor, accepts 8-bit parallel interface、3-line or 4-line serial peripheral interface (SPI)、I2C interface, display data can stores in an on-chip display data RAM of 66 x 102 bits. It performs display data RAM read/write operation with no external operating clock to minimize power consumption. In addition, because it contains power supply circuits to drive liquid crystal, it is possible to make a display system with the fewest components.

FEATURES
Single-chip LCD controller & driver
Driver Output Circuits
102 segment / 65 common + 1 ICON
On-chip Display Data ram
- Capacity: 66X102=6,732 bits Microprocessor Interface
    - 8-bit parallel bi-directional interface with 6800-series or 8080-series
    - 4-line SPI (serial peripheral interface) available (only write operation)
    - 3-line SPI (serial peripheral interface) available
    - I2C (Inter-Integrated Circuit) Interface
On-chip Low Power Analog Circuit
    - Generation of LCD supply voltage (externally Vout voltage supply is possible)
    - Generation of intermediate LCD bias voltages
    - Oscillator requires no external components (external clock also possible)
    - Voltage converter (x4, x5)
    - Voltage regulator(temperature gradient -0.11%/°C)
    - Voltage follower
    - On-chip electronic contrast control function (255 steps)
External RESB (reset) pin
Logic supply voltage range VDD1,2 -VSS
    - VDD1 -VSS : 1.7 to 3.3V
    - VDD2 -VSS : 2.4 to 3.3V
Display supply voltage range VLCD -VSS
    - 4.5 to 13.5V
Temperature range: -40 to +85 degree