Dear Gustava,

Problem solved. In the code was #define LCD_I2C_OFF and it should have been #define LCD_I2C_ON. Everything is working now after the change.

All the best

Peter

Dear jgustavoam I have programmed an DOIT ESP32 with your Frequency Counter program everything works well I can get the Frequency readout on the Serial Console. and change Frequency as well. I just have a problem with the attached serial LCD. I have changed the address in your program to 0x27, howev...