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STM32F407 : IWDG and erase flash sector

Question asked by Pablo.Devanne on Mar 20, 2017
Latest reply on Mar 24, 2017 by Pablo.Devanne

Hi,

 

In my application I'm using the Independent watchdog on a STM32F407 with a maximum reload period of 2 ms. During some maintenance operations, we need to save some configuration parameters in flash memory. Even if we use the 16 kB sector, the erase time is greater than 2 ms and the IWDG make the MCU reset. Because there is only on flash bank on the 407 I can't kick the watchdog during the flash erase operation (and the bus stalls anyway), and it is not possible to disable the IWDG.

 

In order to avoid these resets, I tried to reconfigure the IWDG with a max reload period of a few seconds which is, I measured, way greater than the time needed for the erase operation.

In debug, the registers of the IWDG looks fine after the reconfiguration but when I tried in release or in debug but with no break point near the erase sector routine I have a IWDG reset.

 

Is there any way to avoid this behavior or am I just not correctly reconfiguring the IWDG ?

 

Many thanks in advance,

Pablo

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