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CCS/EK-TM4C129EXL: I2C (master_slave)

B.M
Expert 1660 points
Part Number: EK-TM4C129EXL

Tool/software: Code Composer Studio

Hello everyone i am trying to send data from master module (I2C0) to slave module (I2C2) without loop-back when i run the code loop-back is still implementing 

could anyone who is familiar with I2C help me

  • 0
    TI__Guru**** 183736 points

    Hi,

      Can you first tell what is not working instead of having your helpers to go through the entire code? If you are connecting the I2C0 and I2C2 on the bus then you must have proper pullup resistor on SCL and SDA bus. Do you have that? Do you have either logic analyzer capture or the scope capture of the I2C bus?

  • 0 in reply to Charles Tsai
    Expert 1660 points

    actually i didn't connect pullup resistors to SCL and SDA 

    What's the recommended value for them. did you track the code above is everything correct?

  • 0 in reply to B.M
    TI__Guru**** 183736 points

    Hi,

      You can start with 4.7k as a rule of thumb. If you want to be precise you can refer to this app note on pull resistor calculation.http://www.ti.com/lit/SLVA689. I think between 4.7k to 10k should be fine for most applications. 

      I think once you add the pullup, you can easily debug your code with the aid of the scope or LA. Glancing your code, I don't spot something wrong. 

  • 0 in reply to Charles Tsai
    Expert 1660 points

    Thanks the I2C works now