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TPS544C26: Read/write under SVID mode

Neo.Wang
Intellectual 900 points
Part Number: TPS544C26

Hi TI experts,

I use TPS544c26 for Intel CPU DDR4 VDDQ rails with SVID protocol.

Questions:

1. Can we read voltage/current/temperature through I2C interface (here FPGA is the I2C master) under SVID mode? If so, how to translate the readout Hex values into actual voltage/current/temperature values?

2. Under SVID mode, how to do Voltage Margining for on-line voltage adjustment? Shall we modify SVID to I2C control and then modify the VOUT_COMMAND register? Please share the procedure.

Thanks

Neo.

  • 0
    Intellectual 900 points

    3. In software I2C read, we observed intermittent failure in repeatedly read, for example when we read "STATUS_VOUT" repeatedly for 50 times, we observed 1-2 times NACK error randomly. Do you have any idea on why this happens? Can we do repeated I2C read through FUSION GUI for debug?

  • 0
    TI__Genius 11315 points

    Hey Neo,

    The voltage/current/temperature conversion equations are found in section 7.3.19 Telemetry of the dataqsheet. The part will continue to be available to read through I2C while in SVID mode. 

    See below table 7-4 for how the part responds to commands from SVID and I2C under different modes. 

    When in SVID + I2C mode, the part will update the I2C Vout offset on the next start-up, meaning enable is toggled or there is a power cycle (make sure to save to the NVM before power cycling).

    To answer your 3rd question, you can do I2C read through the FUSION GUI, and we recommend using the FUSION GUI when debugging. There is a I2C debug tool available underneath the "tools" tab on the I2C Fusion GUI.

    Thanks,
    Caleb