General Description :
ST7921 is a segment driver for dot matrix type LCD  display. It features 96 channels with  48  X  2  bits  bi-directional  shift  registers,  data  latches,  LCD  drivers  and  logic control  circuits.  It  is  fabricated  by  high  voltage  CMOS  process  with  low  current consumption.

FEATUREs :
Display driving bias : static to 1/5
Power supply for logic : 2.7V ~ 5.5V
Power supply for LCD voltage (V0~VSS) :   3V ~ 7V
Dot matrix LCD driver with two 48 channel outputs
Bias voltage (V0 ~ V4) 
nput/Output signals
  Input : Serial display data and control pulse from controller IC

  Output : 48 X 2 channels waveform for LCD driving