Figure 353. I2C Bus Protocol - ST STM32L4x6 Reference Manual

RM0351 Inter-integrated circuit (I2C) interface
In Slave mode, the interface is capable of recognizing its own addresses (7 or 10-bit), and
the General Call address. The General Call address detection can be enabled or disabled
by software. The reserved SMBus addresses can also be enabled by software.
Data and addresses are transferred as 8-bit bytes, MSB first. The first byte(s) following the
START condition contain the address (one in 7-bit mode, two in 10-bit mode). The address
is always transmitted in Master mode.
A 9th clock pulse follows the 8 clock cycles of a byte transfer, during which the receiver must
send an acknowledge bit to the transmitter. Refer to the following figure.
2
Figure 353. I C bus protocol
Acknowledge can be enabled or disabled by software. The I2C interface addresses can be
selected by software.
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