ST STM32G474

Inter-integrated circuit (I2C) interface RM0440
1900/2126 RM0440 Rev 4
Figure 653. Transfer sequence flowchart for SMBus slave transmitter N bytes + PEC
Figure 654. Transfer bus diagrams for SMBus slave transmitter (SBC=1)
MS19867V2
Slave initialization
SMBus slave
transmission
Write I2C_TXDR.TXDATA
I2C_ISR.TXIS
=1?
No
Yes
I2C_ISR.ADDR =
1?
Yes
No
Read ADDCODE and DIR in I2C_ISR
I2C_CR2.NBYTES = N + 1
PECBYTE=1
Set I2C_ICR.ADDRCF
SCL
stretched
MS19869V2
Example SMBus slave transmitter 2 bytes + PEC,
EV1: ADDR ISR: check ADDCODE, program NBYTES=3, set PECBYTE, set ADDRCF
EV2: TXIS ISR: wr data1
EV3: TXIS ISR: wr data2
ADDR
legend:
transmission
reception
SCL stretch
EV1 EV2
TXIS
TXIS
EV3
NBYTES 3
S Address A Adata1
data2
PEC
A
NA
P