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I2C register access not working

Tobias Heil21
Prodigy 40 points

Part Number: CDCI6214

Hi everyone,

we recently moved to a new hardware sample with our product.

Related to the CDCI6214 we did not change anything, however with the new hardware sample I am not able to access the device via I2C anymore.

 

I do not get an acknowledge for any of the possible device address.

I already measured the I2C signals, the power supplies and the reset wire but they are all just fine.

I also tried to set the device in the fallback mode but this did also not change anything.

 

Do you have any idea why I cannot access the device anymore?

 

Thank you very much

BR

Tobias

 

  • 0
    TI__Mastermind 34340 points

    Hi Tobias,

    Is this an issue with multiple devices, or just this device? Have you tried replacing the device?

    Regards,

  • 0
    TI__Prodigy 550 points

    Hello Tobias,

    To be sure, could you please float pin 4(REFSEL), Pin 8(RESETN) and Pin 23(EEPROMSEL) and try if you can access the device through I2C?

    I2C access can be disabled if RESETN is pulled LOW or Non-Interface mode is configured in EEPROM? Floating Pin #4 and #23 would set it at Mid level. Floating #8 would pull it high internally.

    What are the power supply levels on 4 supply pins of the device?

    Regards,

    dinesh.

  • 0 in reply to Derek Payne
    Prodigy 40 points

    Hi Derek,

    thanks for your response.

    We assembled a rather small charge, so I have only 16 PCBs with the CDCI.

    But all of them show the same behavior.

    I will try to replace some of the devices anyway.

    BR

    Tobias

  • 0 in reply to Tobias Heil21
    TI__Mastermind 34340 points

    Hi Tobias,

    I think it would be very unlikely for all 16 CDCI devices to have the same issue by chance. Can you please confirm that the fall-back procedure you attempted matches the following procedure?

    1. Completely float REFSEL pin (no connection)
    2. Completely float EEPROMSEL pin (no connection)
    3. Tie RESETN pin to VDDREF pin
    4. Power Cycle the device
    5. Check for device on address 0x74

    Even if this procedure matches exactly, can you please perform it one more time, and measure the final voltage at the I2C data pin? This will help me figure out what the CDCI6214 thinks it sees on the REFSEL/EEPROMSEL/RESETN pins after power cycling.

    Regards,

  • 0 in reply to Derek Payne
    TI__Mastermind 18070 points

    Hi Tobias,

    Are you using the TI EVM? It is a bit tricky to enter fall-back mode using this EVM and the corresponding GUI, because the GPIO pins are constantly pulled by the software, sometimes incorrectly. The way I dealt with it was to remove resistor R174, R190 and R157 (next to J19, J22, J16 separately). By doing so, the GUI can no longer control these pins so that you can enter the fall back mode simply by removing the jumpers for J19 and J22.

    You can also turn off all 4 switches of S2 (close to the jumpers for LDO). This way the device is always powered on regardless of the GUI. Please try this and let me know if you have any question.

    Regards,

    Hao

  • 0 in reply to Hao Z
    TI__Mastermind 18070 points

    Hi Tobias,

    Did this solve your problem?

    Regards,

    Hao