The Tiny RTC board incorporates two I2C modules, one RTC IC (DS1307) and one EEPROM IC (AT24C32), which is ideal for learning how to setup a multi-client I2C bus communication. The main purpose of this repository is to provide an I2C reference solution running on Arduino HW implemented in Atmel Studio.

This firmware uses the C-implementation of the Arduino TWI-library (minor patch for the SDA/SCL pull-ups) which is then abstracted by an I2C-wrapper. The test and verifications has been done on an Arduino Mega which holds an ATmega2560 MCU. Due to trademark issues the Atmel MCUs names it's I2C function to TWI (Two Wire Interface) but the functions are more or less identical (and compatible with each other). More information about this can be found [here] (http://www.i2c-bus.org/twi-bus).

The are many variants of the board but, essentially, the ICs and the pin-outs are the same. A good description of the board's functions and accompanied connections can be found here.

RTC DS1307 datasheet

EEPROM AT24C32 datasheet

A cheap place to buy the board from:

http://www.elecrow.com/sensor-c-111/misc-c-111_115/tiny-rtc-for-arduino-p-323.html