Problem with begin(20,4) for 20 by 4 display

[fletchjp]

I have some code which I have been running using LiquidCrystalIO with a 20 by 4 LCD display. I have not used it for some time and when I recompile the display no longer works - it goes black and resets the LCD in some way.

I have experimented with the code and examples work e.g. your HelloI2C as long as I use begin(16,2).

Code using a direct call to hd44780_I2Cexp to set up the LCD works fine with begin(20,4).

I am using an Arduino MEGA and a display with I2C 0x27 and using LiquidCrystalI2C_RS_EN.

I have had a look at the library code and cannot spot anything obvious in the code changes.

John Fletcher

[fletchjp]

I am using version 1.4.3 of LiquidCrystalIO as released through the Arduino Library management system, along with other libraries of the family.

[fletchjp]

I have found the answer to my problem. I was missing this code, which is in your example helloI2c

// most backpacks have the backlight on pin 3.
lcd.configureBacklightPin(3);
lcd.backlight();

When I put that into my example it all works again. Cheers John

[fletchjp]

I think that the configureBacklightPin code used to be in a constructor. That explains why my code used to work....
John