I2C Module Registers
1068
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Inter-Integrated Circuit Module
Table 14-15. Dependency of Delay d on the Divide-
Down Value IPSC
IPSC
d
0
7
1
6
Greater than 1
5
14.5.8 I2C Slave Address Register (I2CSAR)
The I2C slave address register (I2CSAR) is a register for storing the next slave address that will be
transmitted by the I2C module when it is a master. It is a 16-bit register with the format shown in
. As described in
, the SAR field of I2CSAR contains a 7-bit or 10-bit slave
address. When the I2C module is not using the free data format (FDF = 0 in I2CMDR), it uses this
address to initiate data transfers with a slave or slaves. When the address is nonzero, the address is for a
particular slave. When the address is 0, the address is a general call to all slaves. If the 7-bit addressing
mode is selected (XA = 0 in I2CMDR), only bits 6-0 of I2CSAR are used; write 0s to bits 9-7.
Figure 14-25. I2C Slave Address Register (I2CSAR)
15
10
9
0
Reserved
SAR
R-0
R/W-3FFh
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 14-16. I2C Slave Address Register (I2CSAR) Field Descriptions
Bit
Field
Value
Description
15-10
Reserved
These reserved bit locations are always read as zeros. A value written to this field has no effect.
9-0
SAR
In 7-bit addressing mode (XA = 0 in I2CMDR):
00h-7Fh
Bits 6-0 provide the 7-bit slave address that the I2C module transmits when it is in the master-
transmitter mode. Write 0s to bits 9-7.
In 10-bit addressing mode (XA = 1 in I2CMDR):
000h-3FFh
Bits 9-0 provide the 10-bit slave address that the I2C module transmits when it is in the master-
transmitter mode.
14.5.9 I2C Own Address Register (I2COAR)
The I2C own address register (I2COAR) is a 16-bit register.
shows the format of I2COAR,
and
describes its bit fields. The I2C module uses this register to specify its own slave
address, which distinguishes it from other slaves connected to the I2C-bus. If the 7-bit addressing mode is
selected (XA = 0 in I2CMDR), only bits 6-0 are used; write 0s to bits 9-7.
Figure 14-26. I2C Own Address Register (I2COAR)
15
10
9
0
Reserved
OAR
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 14-17. I2C Own Address Register (I2COAR) Field Descriptions
Bit
Field
Value
Description
15-10
Reserved
These reserved bit locations are always read as zeros. A value written to this field has no effect.
9-0
OAR
In 7-bit addressing mode (XA = 0 in I2CMDR):
00h-7Fh
Bits 6-0 provide the 7-bit slave address of the I2C module. Write 0s to bits 9-7.
In 10-bit addressing mode (XA = 1 in I2CMDR):
000h-3FFh
Bits 9-0 provide the 10-bit slave address of the I2C module.