I'm looking for suitable GLCD, so far I have found the RX12864H, however the datasheet describes a lot of voltages and I'm bit confused.

While the VSS and VDD are clear to me, I have no clue what do the V0, XV0 and VG mean. The internet research lead me to using V0 like contrast adjustment, but I still know nothing about the XV0, and the "LCD driving voltage for common circuits at positive frame" isn't very understandable for me. The datasheet specifies the Vop for typically 10V, which for me looks like really big value for the LCD powered by 3.3V, also I can't find any min/max rating for the VG.

Snip from the datasheet:Snip from datasheet

The full datasheet can be found here: Datasheet

  • \$\begingroup\$ X in XV0- positive frame? Without X in V0- negative frame? It doesn't look conventional so it's probably arbitrary reference designation. \$\endgroup\$
    – user103380
    Commented Jul 17, 2018 at 19:36
  • 1
    \$\begingroup\$ It says +10V typ for both frame supplies. 2mA typ for dynamic charge bias \$\endgroup\$ Commented Jul 17, 2018 at 19:50

1 Answer 1


You can connect those pins to 3.3v if not mentioned. Anything more than 3.3v without mentioned can be disastrous. The V0, XV0,VG is used to power segment drivers and common circuit drivers inside the LCD. Without powering thses pins,you can't able to see images in LCD but it still accepts the commands and works fine. The Vdd and Vss is to power the microcontroller inside the LCD to work. The V0,XV0and VG is used to power the display to show images. LCD with COM lines and SEG driver lines

You can see from the picture that you have COM and SEG lines.These will drive the Liquid crystals inside LCD which inturns shows you as dots. To get that image ,you need to provide separate power right, that is what the purpose of V0,VG and XV0 pins. In datasheet they also have a capacitor between then and ground for avoiding surge voltages and noise from power supply.internal structure of LCD

You can see that power for display , they provided these pins. I also found the necessary supply that has to be provided from the LCD driver datasheet poer requirements

Kindly refer ST7567.pdf to know more about driving the display and power supply requirements.


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