14.3.6.2 10-Bit Addressing Format
The 10-bit addressing format can be enabled by setting expanded address (I2CMDR.XA = 1) and disabling free
data format (I2CMDR.FDF = 0).
The 10-bit addressing format (see
) is similar to the 7-bit addressing format, but the master sends
the slave address in two separate byte transfers. The first byte consists of 11110b, the two MSBs of the 10-bit
slave address, and R/ W. The second byte is the remaining 8 bits of the 10-bit slave address. The slave must
send acknowledgment after each of the two byte transfers. Once the master has written the second byte to the
slave, the master can either write data or use a repeated START condition to change the data direction. For
more details about using 10-bit addressing, see the NXP Semiconductors I2C bus specification.
S
1
1 1 1 1 0 x x
7
x x x x x x x x
ACK
1
1
8
ACK
1
Data
n
ACK
1
P
1
x x = 2 MSBs
R/W
8 LSBs of slave address
Figure 14-11. I2C Module 10-Bit Addressing Format (FDF = 0, XA = 1 in I2CMDR)
14.3.6.3 Free Data Format
The free data format can be enabled by setting I2CMDR. FDF = 1.
), the first byte after a START condition (S) is a data byte. An ACK bit is inserted
after each data byte, which can be from 1 to 8 bits, depending on the BC field of I2CMDR. No address or
data-direction bit is sent. Therefore, the transmitter and the receiver must both support the free data format, and
the direction of the data must be constant throughout the transfer.
Data
Data
S
1
Data
ACK
ACK
ACK
P
1
n
n
n
1
1
1
Figure 14-12. I2C Module Free Data Format (FDF = 1 in I2CMDR)
Note
The free data format is not supported in the digital loopback mode (I2CMDR.DLB = 1).
Table 14-4. How the MST and FDF Bits of I2CMDR Affect the Role of the TRX Bit of I2CMDR
MST
FDF
I2C Module State
Function of TRX
0
0
In slave mode but not free data
format mode
TRX is a don’t care. Depending on the command from the master, the I2C
module responds as a receiver or a transmitter.
0
1
In slave mode and free data
format mode
The free data format mode requires that the I2C module remains the
transmitter or the receiver throughout the transfer. TRX identifies the role of
the I2C module:
TRX = 1: The I2C module is a transmitter.
TRX = 0: The I2C module is a receiver.
1
0
In master mode but not free data
format mode
TRX = 1: The I2C module is a transmitter.
TRX = 0: The I2C module is a receiver.
1
1
In master mode and free data
format mode
TRX = 0: The I2C module is a receiver.
TRX = 1: The I2C module is a transmitter.
Inter-Integrated Circuit Module (I2C)
846
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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