NHD-C0220BiZ-FS(RGB)-FBW-3VM I2C Help

kharding

• March 18, 2019 08:07

Hello all,

I am using a NHD-C0220BiZ-FS(RGB)-FBW-3VM with I2C functionality. I have been able to get this LCD working before but now I am having troubles with SDA and SCK. I have tried multiple different resistances and multiple addresses. I am using the address of 0b01111000 (0x78) and have tried multiple resistances on the pull up lines. If the resistance is too high, the SDA and SCK lines will drop to 1.5V. If the resistance is about 1K the lines are able to send data from my controller, but I believe the LCD cannot pull the line low to acknowledge the command. It seems like the LCD is drawing a lot of current on the SDA and SCL lines. Is this a thing?

Thanks in advance!

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  Ted M.

  NHD Staff

  • March 20, 2019 08:07

  Hi kharding,
  
  Please check and confirm the "L" level input is less than 0.8V and the "H" level input is more than 2.31V to be withing the specification. 
  It may also be good to check the noise level on the source waveform using a scope as this may affect the logic level transitions.
  
  Best Regards,

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