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P82B96: I2C communction with TCA9416DDFR and P82B96

Ethan Ku
Prodigy 120 points

Part Number: P82B96
Other Parts Discussed in Thread: TEST2, TCA9416

Hi TI 
our produce is power shelf (PSU*6+PDB+PMC)
 
 
Test1:
         PSU*1+PDB+PMC I2C communication is OK
 
Test2:
        An I²C communication issue was observed when PSU2 was connected to the main bus in parallel. The MCU is suspected to be damaged, and further investigation is ongoing. Upon reviewing the bus, multiple pull-up resistors with different resistance values were identified, as i shared.
Could you kindly confirm whether these pull-up resistor values are appropriate, and advise if they should be standardized or reduced? Furthermore, please confirm whether the power rail configuration is correct
 
image.png
  • 0
    TI__Guru 57481 points

    Hi Ethan,

    Are there any passive components on PSU2 PCB? If so, can we double confirm that the updated sinking current from all the PCBs can be handled by the MCU when its driving a low state? If there are any waveforms that can be provided regarding I2C communication issue, that may be helpful for debugging. Please note that TCA9416 also has internal pullups already. Any external pullups will form a parallel network and increase current draw during low state (IOL) and further increasing VOL levels.

    Regards,

    Jack

  • 0
    TI__Guru 62018 points

    Hi Ethan,

    Can you provide more details on the schematic for PSU2 PCB? What additional load is added to the I2C bus with the connection of PSU2_PCB? 

    Has the damaged been confirmed on MSPM0G3507SPMR? 

    Regards,

    Tyler