I2C
From S1MP3 Wiki
General
If you are not familiar with I²C as a serial bus standard, read more about it here. The ATJ's I²C controller supports both, master and slave mode, with standard (100 kbps) and high (400 kbps) speed. To activate this piece of hardware, its necessary to leave GPIO mode (F1) first and switch to any other mode (Fx, x > 1).
Related pages
Debug interface - debug interface using the i²c bus

