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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



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,