I2C is not working for receiving data - RXNE flag is not getting set

[sandeepBJadhav]

Hi,

I am working on STM32MP133FAFx (I2C Master) for I2C communication with STPMIC1 IC (I2C slave) fast mode(400KHz) and HSI clock(64MHz). I2C->TIMINGR = 0x00C0216C

For writing data TXIS flag is getting send and I am writing the register but when trying to read data back from PMIC RXNE flag is not getting set and RXDR register is not showing data.

Configuration for reading & writing data is done as per the example code provided by ST

i.e. used  HAL_I2C_Mem_Read() & HAL_I2C_Mem_Write() functions for 1 byte data transfer.

Please help me how to resolve this issue and provide me the solution.

[PatrickF · Accepted solution]

Hi @sandeepBJadhav 

low level I2C could be quickly checked using a simple oscilloscope probing SCL and SDA.

Then you could check:

- possible issue with bus level/timing (e.g. missing 1.5k pull-ups)

- correct I2C sequence including address/RW/ACK

- presence of STPMIC1 answer

Regards.