LCD DRIVING METHOD
The liquid crystal must be driven with alternating voltage. DC drive would destroy the liquid crystal. This AC drive requirement is the main factor for any power consumption. The electrical equivalence for the driving stage is a capacitor. Its electrodes are the backplane or common plane, controlled by signal COM and the segment driven by SEG. The frequency of the AC drive is low - in the range of 1000 Hz to 30 Hz. Therefore, users prefer external LCD drivers (eg HT1621B, PCF85176) or microcontrollers with integrated LCD driver (eg HT67Fxx, ATmega169A). Thanks to these drives, the microcontroller is not kept in continuous cycle and a faster solution is developed.
Source Code Example: HT1621_LCD_Drive