Data Sheet




15
= 1.1V
3.6 I2C Protocols
The I2C Controller has the following protocols:
● START and STOP Conditions
● Addressing Slave Protocol
● Transmitting and Receiving Protocol
● START BYTE Transfer Protocol
3.6.1 START and STOP Conditions
When the bus is idle, both the SCL and SDA signals are pulled high through external pull-up
resistors on the bus. When the master wants to start a transmission on the bus, the master issues a
START condition. This is defined to be a high-to-low transition of the SDA signal while SCL is 1.
When the master wants to terminate the transmission, the master issues a STOP condition. This is
defined to be a low-to-high transition of the SDA line while SCL is 1. Below figure shows the timing
of the START and STOP conditions. When data is being transmitted on the bus, the SDA line must
be stable when SCL is 1.
Figure. Start and Stop conditions
Note: The signal transitions for the START/STOP conditions, as depicted in above figure, reflect
those observed at the output signals of the Master driving the I2C bus. Care should be taken when
observing the SDA/SCL signals at the input signals of the Slave(s), because unequal line delays
may result in an incorrect SDA/SCL timing relationship.
3.7. UART interface
The AW-CU429(DA14691) contains two identical instances of this block, i.e. UART and UART2.
The UART is compliant to the industry-standard 16550 and is used for serial communication with a