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CCS/TMS320F28335: I2C Communication with PCA9539DGVR

omer gundogmus
Intellectual 345 points

Part Number: TMS320F28335

Tool/software: Code Composer Studio

Hello,

I am trying to read data from PCA9539DGVR with I2C communication. I have tried example code in the attachment but I can not read data. Slave Address is 0x76. In I2C data receive register shows always 0.(please see in the attachment)  

Please could you help me to find out the problem. 

Regards,I2C Fault.docx

I2C_register.docx

Omer

  • 0
    TI__Mastermind 45606 points
    Hi Omer,

    I'd recommend looking at the datasheet for the PCA9539DGVR. The I2C comms format for a read looks like it should be the following:

    Slave Addr --> Command Byte --> Slave Addr --> Receive 1st Byte --> Receive 2nd Byte --> etc...

    It looks like your missing the first part of the comms for sending the Command Byte in your code. Also, could you check the waveforms of the communication on the bus? make sure you can see the proper slave address with ACK and everything after.

    Hope this helps,
    Kevin