dniklaus / arduino-display-lcdkeypad Goto Github PK

The LiquidTWI2 driver is not loaded if the application doesn't initialize the I2C system with

Wire.begin();

before the LcdKeypad object gets created. With this missing initialization step, the HW presence check fails and the LiquidCrystal object will be created instead.

Just stumbled upon the following warning to users of some vendors LCD keypad shields in the Arduino Forum / Display section.

WARNING! This component is potentially damaging your Arduino!
DO NOT USE THIS COMPONENT AS LONG AS THIS ISSUE IS NOT FIXED!

LCD Keypad HW Schematic

Simple SW fix:
In the method void LcdKeypad::setBackLightControl() do the following:

• to turn the backlight on, set digital pin 10 to INPUT and write a low value in order to disable the internal pull-up resistor
• to turn the backlight off, set the digital pin 10 to OUTPUTand write a low value

Will this work on a 16x2 lcd keypad shield?