My device is setting watchdog during powerup.

VinayakP · ‎2021-08-04

Dear ST community,

We are using STM32L152VBT6-LQFP100 Pin IC in our device. we are using it for a long time.

recently we observed that our 2 boards are setting watchdog during Powering the Board.

the boards are going in the loop of watchdog reset. what can be the possibilities for causing WDC and how can we resolve this issue.

Thanks in advance.

Tesla DeLorean · ‎2021-08-04

Probably going to have to do some debugging or add some diagnostics to understand where it is hanging up.

Look for infinite while loops like those typically found in Error_Handler() or HardFault_Handler(), etc. Issues where clocks or PLLs don't start as expected, or other timeout loops where things are expected to happen but don't.

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waclawek.jan · ‎2021-08-04

> 2 boards are setting watchdog during Powering the Board

?

JW

VinayakP · ‎2021-08-04

Hey Tesla,

Thanks for the reply.

The same code is working perfectly on the other 40 boards.

The issue is only on 2 boards and we cant figure out where is the problem and how it is caused.

VinayakP · ‎2021-08-04

Hey waclawek.jan,

Thanks for the reply.

The same code is working perfectly on the other 40 boards.

The issue is only on 2 boards and we cant figure out where is the problem and how it is caused.

waclawek.jan · ‎2021-08-04

Have you checked the Option Bytes (namely the IWDG_SW bit in them) on those 2 boards?

JW

Kraal · ‎2021-08-04

If the issue is only present on 2 boards and the others are working as they should, I would suspect a hardware defect on those 2 boards (probably from manufacturing).

Since the watchdog is kicking in, I would look for endless loop conditions like waiting for the LSE to startup correctly, or something like this.

VinayakP · ‎2021-08-04

Hey waclawek.jan,

Thanks for the reply

after talking with my team they said we are using only (RCC_FLAG_IWDGRST) Register in our code.

VinayakP · ‎2021-08-04

Hey Kraal,

Thanks for the response.

we have checked the hardware on both the PCB's. checked the connections, voltage is stable, drowning normal current. and we are able to communicate with the board (TX/RX). but not able to rectify why it is setting WDC.

waclawek.jan · ‎2021-08-04

I don't know what is RCC_FLAG_IWDGRST.

I am asking about the Option Bytes, i.e. nonvolatile bytes which may be programmed during device programming.

JW