[u8x8.setContrast] does not work / Please help me.

[SeongJongKwak]

Reference link 1: How to set contrast on a 128x128 px (ssd1327) oled display 1 Reference link 2: SSD1306 u8x8.setContrast(0-255) aint working · Issue #686 · olikraus/u8g2 · GitHub 1

MCU : STM32Duino STM32F103C8

U8X8_SSD1306_128X32_UNIVISION_SW_I2C u8x8 [u8x8.setContrast] does not work.

hello. Other operations work fine using the 'u8x8' library. I want to use it with low power.

Software case(1) u8x8.setContrast(0);

Software case(2)

  u8x8_cad_StartTransfer(u8x8.GetU8x8());
  u8x8_cad_SendCmd( u8x8.GetU8x8(), 0xD9);
  u8x8_cad_SendArg( u8x8.GetU8x8(), 0);  
  u8x8_cad_EndTransfer(u8x8.GetU8x8());

I use the command above, but 0 and 255 make no difference.

Is there a software solution? does not work. In terms of hardware, I replaced 'R5' in the picture with a resistor as large as possible. ex) R5 = 3M[Ohm] Neither 1 nor 2 affect brightness. help me.

[olikraus]

There are many more issues related to this topic, just mentioning some of them:

https://github.com/olikraus/u8g2/issues/636

https://github.com/olikraus/u8g2/issues/1833

All in all this is very hardware specific and has nothing todo with u8g2 as a library.

[SeongJongKwak]

@olikraus

Thanks for your reply.