INTRODUCTION
ST7541  is  a  driver  &  controller  LSI  for  4-level  gray  scale  graphic  dot-matrix  liquid  crystal  display  systems.  This  chip  can connect directly to a microprocessor which supports: Serial Peripheral Interface (SPI), IIC or 8-bit parallel interface. Display data stores in an on-chip display data RAM of 128 x 129 x 2 bits. It performs display data RAM read/write operation with no external operating clock to minimize power consumption.

FEATURES
4-level Gray Scale
–Display with PWM and FRC Methods
Driver OutputCircuits
  128 segment outputs/ 128+1 common outputs
ApplicableDutyRatios
– V arious partial display
–Partial window moving & data scrolling
On-chipDisplay Data RAM
–Capacity: 128  ×  129  ×  2=33,024 bits
Microprocessor Interface
–  8-bit  bi-directional  parallel  interface  supports  6800-series or 8080-series MPU
– 4-line serial interface(4-LineSPI)
– 3-line serial interface(3-Line 8-bit SPI)
– IIC serial interface
On-chip Low PowerAnalogCircuit
– On-chip oscillator circuit
– Voltage booster (x3, x4, x5 or x6)
– Voltageregulator (temperature coefficient: -0.144%/˚C, or external input)
– On-chip electronic contrast controlfunction(64 steps X 8)
– Voltage follower (LCD bias: 1/5to 1/12)
Operating V oltage Range
–Supply voltage(VDD): 1.8to 3.3V
–Supply voltage(VDD2): 2.4 to 3.3V
– LCD driving voltage(VLCD =V0- VSS): 3.5 to 15.0V Package Type
–  Applicationfor COG