Hi Sairam, I recommend checking these items 1) Your display is LCD 16 char x 2 lines + I2C PCF8574? 2) Check the I2c Interface lines: #define I2C_SDA 21 // LCD I2C SDA - GPIO_21 #define I2C_SCL 22 // LCD I2C SCL - GPIO_22 3) Which PCF8574 module are you using? What is the I2C address? LiquidCrystal_...

I am using PC8574 with address 0 x 27 16 x 2 LCD. I tried the hello world sketch it is displaying the message on LCD but in the frequency counter sketch I am able to see the data on the serial monitor but I get only squares in the LCD display I changed the address in the sketch to 0x27.

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 even with the LCD_I2C_ON I am not getting the display. I get only squares. But with other software lcd is working with the sam...