Can anybody suggest an I2C based keypad interface IC, like texas instruments TCA8418.
It must have a keypad encoder and give character outputs through i2c
I suppose you could also use any mcu (pic, avr) to do that job instead of a dedicated chip
and it would also be easily customizable with different keypads.
I don't know the cost of your mentioned chip so i can't judge which solution is cheaper.
You can also use an i2c port expander if you already have an mcu in your project and you don't have the free pins needed to interface the keypad or
you can use the adc converter connected to a keypad wired with resistors, only one adc input is needed in this case. One Input Keypad
Thanks Alex.
Keypad wired with resistors is unconventional. But it have certain problems as told by the author itself. When multiple keys are pressed at the same time, the Voltage values will be unpredictable. I2C port expander is a better solution.