
Rev. 1.00
420 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
20 Inter-Integrated Circuit (I2C)
Features
▆
Two-wire I
2
C serial interface
●
Serial data line (SDA) and serial clock (SCL)
▆
Multiple speed modes
●
Standard mode – 100 kHz
●
Fast mode – 400 kHz
●
Fast mode plus – 1 MHz
▆
Bidirectional data transfer between master and slave
▆
Multi-master bus – no central master
●
The same interface can act as Master or Slave
▆
Arbitration among simultaneous transmitting masters without corrupting serial data on the bus
▆
Clock synchronization
●
Allow devices with different bit rates to communicate via one serial bus
▆
Supports 7-bit and 10-bit addressing modes and general call addressing
▆
Multiple slave addresses using address mask function
▆
Timeout function
▆
Supports PDMA Interface, the PDMA related describes are only available for the HT32F54243/
HT32F54253 devices
Functional Descriptions
Two-Wire Serial Interface
The I
2
C module has two external lines, the serial data SDA and serial clock SCL lines, to carry
information between the interconnected devices connected to the bus. The SCL and SDA lines are
both bidirectional and must be connected to a pull-high resistor. When the I
2
C bus is in the free or
idle state, both pins are at a high level to perform the required wired-AND function for multiple
connected devices.
START and STOP Conditions
A master device can initialize a transfer by sending a START signal and terminate the transfer with
a STOP signal. A START signal is usually referred to as the “S” bit, which is defined as a High to
Low transition on the SDA line while the SCL line is high. A STOP signal is usually referred to as
the “P” bit, which is defined as a Low to High transition on the SDA line while SCL is high.
A repeated START signal, which is denoted as the “Sr” bit, is functionally identical to the normal
START condition. A repeated START signal allows the I
2
C interface to communicate with another
slave device or with the same device but in a different transfer direction without releasing the I
2
C
bus control.