Thanks for the information,
how I can use I2C for display and keypad ?
I can use in meantime for Real Time Clock also ?
Thansk for the the support,
First you would have to aquire a display, keypad, and RTC that all utilize the I2C method of communicating with a I2C master (the arduino controller). All the I2C devices wire to the same I2C clock and data pins on the controller. Each I2C device has a unique device address which allows them to share the bus and allow the master to work with each and all attached devices one at a time. I2C allows up to 127 devices to share the I2C bus.