problem on watchdog

[fabricepeden]

Posted on August 05, 2013 at 14:51

Hi everbody,

I'm using a ST32F205VE. On my board, I'm using the internal watchdog of the microcontroller and an external watchdog (MCP1318T).

During normal operation, the �c sends square pulses every 0.5s to the external watchdog. When the �c stops sending pulses, the external watchdog sends me a rising edge.

Then, the �c is restarting because So it works well.

My issue is when the �c is restarting (with his internal watchdog), I got something strange, because the pulses that the �c is sending to the external watchdog are 3 times longer (0.5s to 1.5s) and I've changed nothing in my configuration.

I'm looking for explanations in the datasheet, but I've found nothing...

If you've some ideas...thank you in advance.

#rcc

[jpeacock2399]

Posted on August 05, 2013 at 15:44

How do you generate the reset pulse to the external watchdog?  Keep in mind that after a reset the STM32 runs on the HSI internal oscillator clock until you change to HSE and/or set the PLL multiplier.

  Jack Peacock