BMA253 SCL always low after power on

[emily]

We use BMA253 in our product, use I2C interface,when power on , MCU output hgih level in SCLpin,  but SCL always low , and the MCU cannot communicate with BMA253, and I want to know why? And what I can do?

[fish]

Hi,

From your photo, there are no pull up resistance of SCL and SDA line, please refer to bma253 datesheet to get the connection diagram of I2C.

Maybe, you could try config SCL(PB10) and SDA(PB11) of STM32L051 internal pull up, meanwhile in I2C mode.

Best regards.

[emily]

R9 and R12 are SCL pull up risistance of SCL and SDA, Value is 10K

[fish]

Sorry, I didn't see this 10K res.

CSB could be float in I2C mode. So please confirm the PB10/11 could run in I2C mode.

[emily]

We use BMA250 bofore, then change to BMA253 because BMA250 EOL, but the firmware not change,still use BMA250, Is there any diffierence between BMA250 and BMA253 aboout firmware(configrataion)?