Generally speaking, the contrast is controlled by voltage. The module power supply has four categories: VDD, GND, VO, and VEE. Among them, the value of VO is the key voltage to control the contrast. We recommend that customers use a 20K VR to connect with VDD, GND or VDD and VEE as voltage dividers, and the obtained voltage divider can be input to VO.

The Vo is the differential voltage between VDD and GND.	When using VEE, the VO is the differrential voltage between VDD and the VEE.