C Addressing Modes; C Module Operating Modes; Bit Transfer On I; Bus - Texas Instruments CC253x User Manual

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20.1.3 I

C Addressing Modes

2
The I C module supports 7-bit addressing mode.
20.1.3.1 7-Bit Addressing
In the 7-bit addressing format (see
The ACK bit is sent from the receiver after each byte.
1
7
S Slave Address
20.1.3.2 Repeated Start Conditions
The direction of data flow on SDA can be changed by the master, without first stopping a transfer, by
issuing a repeated START condition. This is called a RESTART. After a RESTART is issued, the slave
address is again sent out with the new data direction specified by the R/W bit. The RESTART condition is
shown in Figure 20-6.
1
7
S Slave Address
1
Figure 20-6. I
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20.1.4 I

C Module Operating Modes

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The I C module can operate in master transmitter, master receiver, slave transmitter, or slave receiver
mode. The modes are discussed in the following sections.
20.1.4.1 Slave Mode
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Initially, the I C module is configured in receiver mode by setting the I2CCFG.ENS1 bit to receive the I
address. Afterwards, transmit and receive operations are controlled automatically, depending on the R/W
bit received, together with the slave address.
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The I C slave address is programmed with the I2CADDR.ADDR bits. The value of the I2CADDR.GC bit
determines whether the slave responds to a general call.
SWRU191F – April 2009 – Revised April 2014
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Data Line
Stable Data
SDA
SCL
Figure 20-4. Bit Transfer on I
Figure 20-5), the first byte is the 7-bit slave address and the R/W bit.
1 1
R/W ACK
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Figure 20-5. I C Module 7-Bit Addressing Format
1 1 1
8
R/W ACK Data ACK
Any
Number
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C Module Addressing Format With Repeated START Condition

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Change of Data Allowed
2
C Bus
1
8
Data ACK
1 1
7
S Slave Address R/W
1
1
8
Data ACK P
1 1
8
ACK Data ACK
Any Number
Operation
1
1
P
2
C
171
2
I C