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TPS546A24A: Status/Monitor/Clear the SMB_ALRT warning/fault

Part Number: TPS546A24A
Other Parts Discussed in Thread: TPS546C23


I am getting some of the warnings/faults on reading the SMB alert pin.

Does it have any address/register to see the status and take the action (read/write)?

Please suggest how can I read/write or clear the warnings/faults by SW/firmware.

  • SMB_ALERT indicates that there is a bit set in one of the STATUS registers of the device which indicates a warning or fault has occurred.  Since ALERT pins are commonly wire-ORed in a system, SMBus / PMBus also provides a way of identifying the device reporting the alert using the Alert Response Address (ARA) 

    In response to the ALERT being asserted low, the system sense out the Alert Response Address with a READ bit set (the only time PMBus wants to see an address with a Read Bit)  Any device with its ALERT pin asserted low should respond to the ARA request by returning it's address and releasing ALERT.  When multiple devices are asserting ALERT, ARA can be read repeatedly until all devices have reported their address and ALERT is fully released.

    Once the system has collected the address of a device reporting an ALERT, it reads the STATUS_BYTE (0x78) or STATUS_WORD (0x79) commands from PMBus to identify the general type of alert that has been reported, and where to look for more information / details.  Reading STATUS_VOUT (0x7A) STATUS_IOUT (0x7B), STATUS_INPUT (0x7C), STATUS_TEMPERATURE (0x7D), STATUS_CML (0x7E) STATUS_OTHER (0x7F) or STATUS_MFR (0x80) depending on the bits set in STATUS_WORD will provide more details.

    Once the bits have been read, all of the STATUS commands can be cleared with a Send Byte to Command Code 0x03 (CLEAR_FAULTS) or they can be cleared bit-by-bit, by writing b'1 to the bit positions within the individual STATUS commands.

    Since you asked the same question for the TPS546C23, the process is the exact same for that device as for the TPS546x24A family.

  • Hi Peter,

    Thanks for sharing the input.


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    Thank you.