Forums - Difference between Watchdog timer period and timeout

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Difference between Watchdog timer period and timeout
Join Date: 22 Feb 17
Posts: 12
Posted: Wed, 2017-02-22 23:19


I am developing a CSRmesh application.I would like to know following things related to watch dog timer.

1.What is the difference between Watchdog timer period and timeout.? I understand that timeout will reset the application.But what is timer period is doing?

2. What type of watch dog timer is in CSR1010.? Can it reset under hardware issues like some error in oscillation of external crystal?

3.Do the built in watch dog timer can reset under all hanging condition like hanging due to software and hardware?

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abarak Moderator
Join Date: 7 Jun 16
Posts: 13
Posted: Tue, 2017-06-13 06:49
Please look at the fields in CsConfig tool for explanation.
Watchdog consists of 2 tasks:
1. A timer that counts back from "Watchdog timeout" - when reaches 0, resets the chip.
2. A background low priority task that counts back from "Watchdog period" - when reaches 0, "kicks" the first task to start counting from original value.
If the SW hangs for any reason, the second task will not run, therefore will not kick the first one, so the first task will timeout and will reset the chip.
Note comment for "Watchdog timeout":
"must be greater than the watchdog period "wd_period" and is recommended to be at least 125% of that value."
This is obviously for the second task to kick the first one before it times out.
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