Abstract: For the lower cost and power consumption, STN-LCD has been widely used in low and mid-end mobile applications. Based on the mathematical description, a multiple line addressing scheme is approved. We built a mathematical model that can be synthesized by EDA tools for hardware. Combined with the FRC-PWM solution of grey shading, the model is validated by FPGA. As a result, the circuit is optimized for guaranteeing the display quality of CSTN-LCD.