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TPS65987D: I2C1 slave mode NAK, and can not get right value

daniel
Genius 5095 points
Part Number: TPS65987D
Other Parts Discussed in Thread: TPS65987

Hi Team,

Customer want to use I2C1 read a register to confirm if the TPS65987D is awake. (slave address=0x20 @ADCIN2 pull down 10kohm)

They plan to read 0x00(VID) or 0x01(DID), follow d/s figure30 read protocol, but get NAK as attached picture. Also attach .pjt file.

Please kindly help below questions. Thanks

1. Why get NAK from TPS65987D? What is the right value as our .pjt setting?

2. What is the right value of 0x00(VID) and 0x01(DID)? How to set these value by TPS65987 Application Customization tool?

3. Can we change the vendor ID or Product ID of 0x73(Tx Manufacturer Info SOP) by Application Customization tool, and read back this value to confirm if the TPS65987D is awake?

Thanks

0918.pjt

  • 0
    TI__Mastermind 36756 points

    Hi Daniel,

    I would suggest reading the 0x3 register instead, the mode register should read back APP to indicate the TPS65987D is up and running. 

    1. TPS65987D should not send back NAK if the FW is loaded correctly and the device is in APP mode.

    2. VID and DID will return TI SVID by default. There is no need to change these settings or to read them back. I would suggest reading the Mode register (0x3) for your application.

    3. Every time there is any I2C Traffic going to the TPS65987D, it will wake up from sleep state. You can read back any register to do this. It does not need to be any specific register.

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Genius 5095 points

    Hi Eric,

    Thanks for your suggestions.

    We confirmed the FW is ready and function OK, but we still get invalid value(APP mode) as reading 0x03 register.

    We probe I2C SCL/SDA as attached TypeC.zip.

    Sometimes 10KHz CLK can get APP value on 0x03 register, but fail in most time. And always fail as 100KHz CLK.

    Thanks

    TypeC.zip

  • 0 in reply to daniel
    TI__Mastermind 36756 points

    Hi Daniel,

    Can you confirm that you have the correct I2C Pull-up resistors on the I2C lines? They should be pulled up to the LDO_3V3 rail of the TPS65987D. You can refer to the TPS65987EVM as an example.

    Thank you,
    Eric