suspend watchdog

[Adrian]

I am wondering why just sometimes like once in a month my board just stop working and status led stop toogle. Watchdog doesn't react. The status led stays turned on or of. Where can i look for reasons of this behaviour? Ofcourse watchdog is turned on.

[mark]

Hi Adrian

If the watchdog is active it should cause the board to reset if the software were to fail. If the board is freezing I could only imagine two things:

1) The watchdog is being triggered - perhaps it is being triggered very fast (like when the software is in a loop which always triggers it but doesn't do anything else). In this case, always toggling the status LED at the same time would make this visible since the status LED would then also be toggling very fast (which could also look like always on when not measured using an oscilloscope).

2) The system has lost its clock or switched to a low power mode of some sort - in this case the watchdog may also be disabled or also become inactive due to the fast that the clock has also been stopped. Check the modes that your chip supports and see whether there is any way that it could be getting switched to one of them. Note also that the Luminary parts seem to have various problems with the hibernation modes - check the latest errata sheets carefully since they may also give some clues.

Regards

Mark

[Adrian]

Is that possible to system would lost his clock?

[mark]

Hi

Often the is an interrupt from the PLL which signals a loss of lock. In normal situations I would not expect this to ever occur and the interrupt is therefore not supported.

However there must be a reason why the chip manufacturers include this - presumably it can happen, but I would still only expect this to be used as a debugging aid in case of a board which is badly designed (in respect to the PLL layout or with respect to external influences that it needs to be able to tolerate - static discharge, transients and bursts, or temperate ranges) - the interrupt may be useful to detect that this is a weakness in this particular area.

Regards

Mark

[Adrian]

ok , i detected that devices not loses a clock , they freezs only after conncected to the power source, main tasks are starting, including watchdog but not all, i saw like davice after conecting to the power source start most of the task , i saw watschdog is runnign like 2 sec ,and after that jus freezing, if i plug the power source  100 times , ther will be 1 time like led status will be blinking 2 sec and stop after that.