Texas Instruments TMS320C642X manual ICMDR Bit, I2C State, Function of TRX Bit

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Table 16. How the MST and FDF Bits Affect the Role of TRX Bit

ICMDR Bit
MST	FDF	I2C State	Function of TRX Bit
0	0	In slave mode but not free data format	TRX is a don't care. Depending on the command from the master, the I2C
		mode	responds as a receiver or a transmitter.
0	1	In slave mode and free data format	The free data format mode requires that the transmitter and receiver be
		mode	fixed. TRX identifies the role of the I2C:

TRX = 0: The I2C is a receiver.

TRX = 1: The I2C is a transmitter.

10 In master mode but not free data format mode

TRX identifies the role of the I2C:

TRX = 0: The I2C is a receiver.

TRX = 1: The I2C is a transmitter.

1	1	In master mode and free data format	The free data format mode requires that the transmitter and receiver be
		mode	fixed. TRX identifies the role of the I2C:

TRX = 0: The I2C is a receiver.

TRX = 1: The I2C is a transmitter.

Figure 23. Block Diagram Showing the Effects of the Digital Loopback Mode (DLB) Bit

	I2C peripheral
			DLB
To internal I2C logic	SCL_IN		0	SCL
			1	0
From internal I2C logic	SCL_OUT
			DLB
To internal I2C logic
To ARM CPU or EDMA			0	SDA
	ICDRR		ICRSR
		DLB	1	0
From ARM CPU or EDMA	ICSAR	0
From ARM CPU or EDMA	ICOAR	1	ICXSR
From ARM CPU or EDMA	ICDXR
			Address/data

SPRUEN0D –March 2011	Inter-Integrated Circuit (I2C) Peripheral	35
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