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Rev. 1.00
394 of 486
July 31, 2018
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F50231/HT32F50241
19 Inter-Integrated Circuit (I2C)
19 Inter-Integrated Circuit (I2C)
Addressing Format
The I
2
C interface starts to transfer data after the master device has sent the address to confirm the
targeted slave device. The address frame is sent just after the START signal by the master device.
The addressing mode selection bit named ADRM in the I2CCR register should be defined to
choose either the 7-bit or 10-bit addressing mode.
7-bit Address Format
The 7-bit address format is composed of the 7-bit length slave address, which the master device
wants to communicate, with a R/W
bit and an ACK bit. The R/
W
bit defines the direction of the
data transfer.
R/W
= 0 (Write): The master transmits data to the addressed slave.
R/W
= 1 (Read): The master receives data from the addressed slave.
The slave address can be assigned through the ADDR field in the I2CADDR register. The slave
device sends back the acknowledge bit (ACK) if its slave address matches the transmitted address
sent by master.
Note that it is forbidden to own the same address for two slave devices.
ACK
R/W
A0
A1
A2
A3
A4
A5
A6
S
MSB
Slave address
LSB
Sent by slave
S = START condition
R/W = 1: Read direction
= 0: Write direction
ACK = Acknowledge bit
Sent by master
Figure 141. 7-bit Addressing Mode