STMicroelectronics STM32WL5 Series User Manual

RM0453 Rev 5 1093/1450
RM0453 Inter-integrated circuit (I2C) interface
1113
Figure 305. Bus transfer diagrams for SMBus master receiver
34.4.15 Wake-up from Stop mode on address match
This section is relevant only when wake-up from Stop mode feature is supported (refer to
Section 34.3).
The I2C is able to wake-up the MCU from Stop mode (APB clock is off), when it is
addressed. All addressing modes are supported.
Wake-up from Stop mode is enabled by setting the WUPEN bit in the I2C_CR1 register. The
HSI16 oscillator must be selected as the clock source for I2CCLK in order to allow wake-up
from Stop mode.
During Stop mode, the HSI16 is switched off. When a START is detected, the I2C interface
switches the HSI16 on, and stretches SCL low until HSI16 is woken up.
HSI16 is then used for the address reception.
MS19872V2
Example SMBus master receiver 2 bytes + PEC, automatic end mode (STOP)
Address
S
INIT: program Slave address, program NBYTES = 3, AUTOEND=1, set PECBYTE, set START
EV1: RXNE ISR: rd data1
EV2: RXNE ISR: rd data2
EV3: RXNE ISR: rd PEC
A
data1
A
RXNE RXNE
data2
A
NBYTES
NA
legend:
transmission
reception
SCL stretch
3VE1VE
xx 3
INIT
Example SMBus master receiver 2 bytes + PEC, software end mode (RESTART)
Address
S
INIT: program Slave address, program NBYTES = 3, AUTOEND=0, set PECBYTE, set START
EV1: RXNE ISR: rd data1
EV2: RXNE ISR: rd data2
EV3: RXNE ISR: read PEC
EV4: TC ISR: program Slave address, program NBYTES = N, set START
A
data1
A
RXNE RXNE
data2
A
NBYTES
Restart
legend:
transmission
reception
SCL stretch
EV1 EV2
xx
INIT
Address
N
PEC
P
RXNE
EV2
NA
PEC
RXNE
3
EV3
TC
EV4

STMicroelectronics STM32WL5 Series Specifications

General

Brand	STMicroelectronics
Model	STM32WL5 Series
Category	Microcontrollers
Language	English