LCD not displaying data

Other Hardware Displays
5

Hi @berlinss. I see this display uses an RJ11 connector (like an old school landline phone cable). Are you using that connector to connect the display to the Nano R4, or did you instead make the electrical connections via the plated through holes on the circuit board? If the latter, did you solder the connections to the circuit board?

Did you add 4.7k "pull-up" resistors on the I2C lines as specified in the Nano R4 documentation?:

https://docs.arduino.cc/tutorials/nano-r4/user-manual/#ic-communication:~:text=The%20I²C%20protocol%20requires%20pull-up%20resistors

The I²C protocol requires pull-up resistors on both SDA and SCL lines. The Nano R4 board does not have internal pull-ups on A4 and A5 to avoid interference with their analog input functionality, so external 4.7kΩ pull-up resistors to +5 VDC are required for proper I²C operation.

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