Nucleo-G0B1RE I2C2 Communication

[Choudharyas]

I am using the Nucleo-G0B1RE board for I2C communication with BMS AFE IC. I am able to communicate with AFE if i use I2C1 port. I have tested it with [PB9, PB8] and [PA9, PA10]. If i use I2C2 or I2C3 it doesn't work. In case of I2C2 it only works if i use [PA9, PA10] pins that are common pins between I2C1 and I2C2. If i use any other pins of I2C2 and I2C3 it doesn't work. 

As per my application requirement i have to use [PB3,PB4] and it is not working with these pins. Please Help with this

[filipxsikora]

Hello,

hard to tell without any code. Your description "doesn't work" also isn't very informative.

• Check if CLK is enabled for given peripheral
• Do you have CLK enabled for the target GPIO?
• Check if GPIOs are configured correctly for given peripheral
• How do you pull-up your I2C lines? Internally or are they present on the BMS board?
• Using interrupt based transfers? Do you have IRQ enabled for given peripheral?
• Etc etc..

[Andrew Neil]

As @filipxsikora said, you need to provide more details.

https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228

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@Choudharyas wrote:

In case of I2C2 it only works if i use [PA9, PA10] pins that are common pins between I2C1 and I2C2. If i use any other pins of I2C2 and I2C3 it doesn't work. 

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That suggests that the problem lies on those other pins rather that I2C1 vs I2C2.

Pullups?

Have you checked the board's User Manual and/or Schematics to see if PB3,PB4 are "occupied" by anything else?

Have you used an oscilloscope and/or logic analyser to see what's happening on the wires?

Post your schematics.

Show your code.

Do you get HAL error returns in the failing cases?

[Choudharyas]

CLK is enabled for I2C peripheral as well as for GPIO. Pull-up resistor are present on BMS board. The same code is working if i use the I2C1 and for I2C2 also if i use the [PA9, PA10] Pins. I am using CubeMX to generate the code and making all the necessary changes when i change the I2C pins. 

[Choudharyas]

Pull-up resistor are present on BMS board. Hardware and firmware all are same i am only changing the i2C pins and using the cubeMX to generate the code. 

I use logic analyzer and got nothing on that. I also checked the Board schematic and in that PB3 and PB4 are directly connected to 'CN9' connector. 

[Andrew Neil]

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@Choudharyas wrote:

I use logic analyzer and got nothing on that. 

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What about an oscilloscope - it will show "analogue" details that a LA won't.

Can you set PB3,4 just as GPIO outputs, and toggle them?