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Rev. 1.00
422 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
20 Inter-Integrated Circuit (I2C)
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 143. 7-bit Addressing Mode
10-bit Address Format
In order to prevent address clashes, due to the limited range of the 7-bit addresses, a new 10-bit
address scheme has been introduced. This enhancement can be mixed with the 7-bit addressing
mode which increases the available address range about ten times. For the 10-bit addressing mode,
the first two bytes after a START signal include a header byte and an address byte that usually
determines which slave will be selected by the master. The header byte is composed of a leading
“11110”, the 10
th
and 9
th
bits of the slave address. The second byte is the remaining 8 bits of the
slave device address.
S
1
W
S = START condition
W = Write command
A
ck
= Acknowledge
A
9
~ A
0
= 10-bit Address
1
1
1
0
Data
A
9
A
8
A
ck
A
7
A
6
A
ck
A
4
A
3
A
2
A
0
A
1
A
5
MSB
LSB
Figure 144. 10-bit Addressing Write Transmit Mode
S
1
W
S = START condition
Sr = Repeated-START condition
W = Write command
R = Read command
A
CK
= Acknowledge
A
9
~ A
0
= 10-bit Address
1
1
1
0
Data
A
9
A
8
A
CK
A
7
A
6
A
CK
A
4
A
3
A
2
A
0
A
1
A
5
MSB
LSB
1
R
1
1
1
0
A
9
A
8
A
CK
Sr
Figure 145. 10-bits Addressing Read Receive Mode