• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 64 subscribers
  • Views 365 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65381A-Q1: WD_FAIL_CNT in DIAG when Writing WD_WIN1_CFG

Wayne Liu
Expert 8705 points
Part Number: TPS65381A-Q1

Hi,

My customer reported when they write to WD_WIN1_CFG and WD_WIN2_CFG in DIAG, the WD_FAIL_CNT changes to 7 from 5 when it goes to ACTIVE, this forces them to make two good events to decrease the CNT to 5 when it just goes to ACTIVE, is this the normal process? If not, any suggestion for me to debug this issue? Thanks.  

  • 0
    TI__Mastermind 20590 points

    Hi Wayne,

    Anytime the WD_WIN1_CFG or WD_WIN2_CFG registers are written to, the WD_FAIL_CNT will increment by +1 (unless the counter is at the maximum of 7).  A write to these registers also ends the current WD sequence and starts a new one so it is easy for the MCU to synchronize to the TPS65381A-Q1 since the MCU knows a new sequence started immediately after the write to WD_WINx_CFG.  

    As documented in section 5.4.23 ACTIVE state,  "The WD_FAIL_CNT[2:0] counter reinitializes to 5 during a transition from the DIAGNOSTIC state to the ACTIVE state.".   The WD_FAIL_CNT[2:0] counter also reinitializes to 5 during a transition to DIAGNOSTIC state from RESET state and if LBIST is run.

    Thus this seeing WD_FAIL_CNT re-initialize to 5 upon entry to ACTIVE state is expected.

  • 0 in reply to Scott Monroe
    TI__Expert 8705 points

    Scott,

    Thank you.

    To double confirm with you, even if the WD_WIN1_CFG and WD_WIN2_CFG are written during DIAG which causes WD_FAIL_CNT increment by +1 and +1 to 7, the CNT will be reinitialized to 5 upon entry to ACTIVE. Right? 

  • 0 in reply to Wayne Liu
    TI__Mastermind 20590 points

    Hi Wayne,

    Doubly confirmed, it will reinitialize to 5.  Every transition into ACITVE state will re-initialize the WD_FAIL_CNT to 5.  Again this is in the datasheet and fully expected:  As documented in datasheet section 5.4.23 ACTIVE state,  "The WD_FAIL_CNT[2:0] counter reinitializes to 5 during a transition from the DIAGNOSTIC state to the ACTIVE state."

    Scott

  • 0 in reply to Scott Monroe
    TI__Expert 8705 points

    Hi Scott,

    Thanks for the confirmation.

    I also double confirmed with customer, they misled me. The fact is that they configured WD_WINx_CFG before DIAG so the CNT is 7 when it is in DIAG. I know WD_WINx_CFG can only be written in DIAG state, however, looks like it is OK to write them before DIAG, is it true and any potential issue if write WD_WINx_CFG before DIAG? They want to do this to save some configuration time. Thanks. 

  • 0 in reply to Wayne Liu
    TI__Mastermind 20590 points

    Hi Wayne,

    The first state the device enters into after RESET state is DIAGNOSTIC state so it that is when the device should be configured including the WD_WIN_CFGx registers.  The expected flow is to set up the WD as required for the application including the WD_WIN_CFGx registers and then run the diagnostics for the watchdog.