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LM5056 and LM5056EVM

Other Parts Discussed in Thread: LM5056EVM, LM25066, LM5066

I'm testing the LM5056EVM and relevant SW GUI, everithing seems to work well (telemetry, warn/fault limits, etc.) but I'm having the following issue :

 

- Setting any of the entries for the MFR_ALERT_MASK (D8h) via the proper menù in the GUI the result is :

SMBA is asserted (even without any measuremt outside limits) and it remains asserted even after CLEAR FAULT command is sent; the only way to exit this condition is powering off the EVM. The expected behawiour for the ALERT_MASK is to not assert the SMBA even when the masked entry is outside its warn/fault limts.

Is there a bug somewhere (LM5056,  EVM or the GUI) or am I missing something?

Regards,

GianLuca

  • Hi GianLuca,

    Welcome to the E2E forums and thank you for considering TI products for your design! I hope you have a good experience and come back with any additional questions you may have.

    Unfortunately I ran out of LM5056 EVMs on hand, so I cannot quickly test this in my lab for the LM5056 specifically. However, I know the ALERT_MASK works within the GUI for our similar hot swap devices (LM25066, LM5066). I also checked the LM5056 GUI in a special debug mode (internal use only) and it seems to work there as well.

    However, your understanding of the expected behavior is correct. ALERT_MASK should mask the specified warning/fault conditions from triggering SMBA.

    One way to know for sure what is happening would be to view the RAW I2C Traffic Log. This is an advanced feature of the GUI and is very useful to help understand or verify the raw bus communication.

    To view the raw traffic log, on the "Device Menu" panel (the small GUI before selecting and opening the device), click "View" --> "Traffic Log".

    Then double click the LM5056 device to open up in the main GUI.

    From here, you can operate as you normally would, and the traffic log will capture the RAW I2C traffic communication.

    For understanding what ALERT_MASK is doing, I would recommend selecting "View" --> "Device Configuration" and go to the "Fault Behavior" panel on the left-hand side. Then I would recommend clicking the "PMBus Register Page" button (icon is an IC) on the top. This will stop the traffic log and only update sections you click "Update" on. So you can check or uncheck registers such as "STATUS_WORD" or "STATUS_INPUT" and then click "Update Status" which will record all the selected status registers into the traffic log.

    Thanks!

    Alex