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I2C not working on Mapped Pins, why?

MikeP
Associate III

Hello,

I am using an STM32G061K6T (only MCU I could find in stock at the time) and I'm try to communicate with an EEPROM via I2C.

I have the SCL and SDA mapped to PA9 and PA10, respectively with 3K3 Pull up resistors. SDA pin is pulled up and stays up however SCL is High when the MCU is held in reset but then it is pulled low and I don't know why. This happens with an EEPROM connected.

I have mapped SCL and SDA to PB6 and PB7 and this works and I can communicate with the EEPROM.

My questions are:

Why does it work when the pins are mapped differently - am I missing something in the datasheet ?

Why is the pin pulled low when the MCU is awake., despite the 3K3 pullup.

I have also checked for shorts

Any help would be apricated. Thanks, Mike

10 REPLIES 10

Perfect thank you! I was using jumper wires to change my PCB layout to the other pins without having to respin the board but now I don't have to.

Thanks again!