I2C bus gives access to the following devices for control and status:
- Access to EEPROM for the main board, fan tray and PSUs;
- Thermal sensors;
- PSU Controllers;
- CPLD, providing several control/status registers for System and Stacking LEDs and PSU Status;
- SFP, SFP+ and QSFP+ optics information: module presence, transmit disable, receive loss and EEPROM information for the specific optic type;
Hardware interface driver is responsible for correct working I2C bus.