can someone point me out the best source to understand how to interface a 4x4 matrix keypad via I2C link ?
I have already put LCD display and RTC on I2C in my design and want to move the keypad also to I2C.
Like there is an I2CLCD.h library is there any such library for keypad?
thanks
AFAIK there are no keypads with I2C as a native interface, what is needed is often called a "serial backpack" or similar and I suspect that's what is on your LCD.
So if you can't find a product that already does that you'll have to roll your own with an IO expander IC or another processor.
Rob
If you are using the matrix keypad library Arduino Playground - HomePage from the Arduino Playground then Joe Young has extended it to use I2C. You can find the Keypad_I2C library here GitHub - joeyoung/arduino_keypads: arduino libraries for keypad interface on I2C bus. It will require the use of two additional I2C port expander chips but Joe provides documentation and explains everything.