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AWR1642BOOST: AWR1642 watch dog solution

Charles Cheng42
Prodigy 130 points
Part Number: AWR1642BOOST
Other Parts Discussed in Thread: AWR1642, TPS65313-Q1

Hello

As checkedTI SWRA590A application report(Watchdog Timer for mmwave Radar Sensors), it suggests internal and external watch dog solution.

Because our boards design just only use internal watch dog solution, is it enough safe?

 

(1) Did TI have any verification analysis of internal watch dog solution-AWR1642? Any risk for internal watch dog solution?

(2) Which specification does TI recommend for external watch dog design?

  • 0
    TI__Guru 58035 points
    Hello Charles,
    Yes the internal watchdog can be used. You can find the watchdog example code as part of the SDK package (www.ti.com/.../MMWAVE-SDK).
    Incase of watchdog failure an internal warmreset would be triggered. But internally there is no way to trigger a hard reset (the one triggered by toggling nRESET pin).

    For external watchdog, you can use any safety MCU or even a PMIC that support watchdog feature. The AWR1642 device can be programmed to provide the watchdog reonses based on the requirement of the external watchdog device used.

    Regards,
    Vivek
  • 0 in reply to Vivek Dham
    Prodigy 130 points

    Hi Vivek

    thanks for the feedback,

    As the customer just asked me , how to make sure internal watch dog to be an enough safety design? 

    Could "internal watch dog" solve which symptomatic failure? 

    And did TI have any verification analysis of internal watch dog solution-AWR1642 to share me?

  • 0 in reply to Charles Cheng42
    TI__Guru 58035 points
    Hello Charles,
    I am not sure I fully understand the request. Watchdogs are used to attempt a recovery from the CPU stuck/fault state. In this case if the cortex core of 1642 is stuck (for any reason) the watchdog would trigger a soft reset of the core and try to recover.
    If you are asking has the watchdog of AWR1642 been tested, yes it has been tested by injecting intentional faults.

    Regards,
    Vivek
  • 0 in reply to Vivek Dham
    Prodigy 130 points
    HI Vivek
    "PMIC configuration : LP87524J + LC filter " only could use internal WDG, not like LP8770 for Monitoring and safety hooks available, and TPS65313-Q1 for SafeTI ASIL-C at RTM 3Q 2019.
    I knew if basd on ISO-26262 Asil specification, Asil B/C need to meet PMHF< 100FITs.
    LP87524J + LC filter " is low cost solution and only internal WDG , so could meet which level ? Asil A?
  • 0 in reply to Charles Cheng42
    TI__Guru 58035 points
    Hello Charles,
    You are right, for a ASIL system its recommended to have external WD (like from the PMIC) to recover from faults which need hard reset of the device (toggling nReset).

    Regards,
    Vivek
  • 0 in reply to Vivek Dham
    Prodigy 130 points

    Hi Vivek

    But could you provide SPFM/LFM/PMHF value if  "LP87524J + LC filter " with internal WDG design? 

    PS: I said if need to meet Asil B, PMHF need to achieve < 100 FITs.

  • 0 in reply to Charles Cheng42
    TI__Guru 58035 points
    Hello Charles,
    For FIT rated and other safety related information please contact your local TI sales representative. You would need to sign a separate safety NDA.

    Regards,
    Vivek