Intel IXP400 manual Arbitration Loss Error, 2C Driver IxI2cDrv

		Intel® IXP400 Software
		I2C Driver (IxI2cDrv)
Figure 109. I2C Driver Dependencies
Client Application
VxWorks*	I2C Adapter	Linux*
	Module
Access-Layer Interface
I2C Driver		IxOSAL
(Algorithm Module )
Hardware Interface
I2C Interface
		B4374-01

26.3.3Error Handling

The I2C driver is capable of detecting all errors that the I2C hardware is able to provide as listed below:

•Arbitration loss error

•Bus error

Any errors that occur during data transfer which do not fall into the arbitration loss or bus error categories will be classified as a master transfer error (IX_I2C_MASTER_XFER_ERROR).

26.3.3.1Arbitration Loss Error

This error occurs when the I2C hardware of the IXP46X network processors loses master control while it is acting as master. Arbitration loss happens when the unit as master sends a high signal but another master sends a low. The occurrence of two masters on the bus can happen when one I2C unit does not see another I2C unit’s START signal to take master of the bus and then sends it own START signal to take master of the bus. Such an occurrence can happen when an I2C unit just exited reset and has no history of previous signals. When this occurs, the I2C status register will be updated with the arbitration loss by the hardware, and if the interrupt for arbitration loss is enabled, then it will call the interrupt service routine.

Programmer’s Guide	IXP400 Software Version 2.0	April 2005
	Document Number: 252539, Revision: 007	333