Hitex XMC1300 Class B Watchdog POST Timing

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I have a project that uses the XMC1300 Class B library provided by Hitex. The watchdog timer power-on self-test (POST) can be configured with #defines located in ClassB_config.h that set the watchdog timer lower bound (ClassB_TEST_POST_WDOG_WLB) and the watchdog timeout (ClassB_TEST_POST_WDOG_TIME).

The comment for ClassB_TEST_POST_WDOG_WLB states:
// Timeout WLB value for the WDT <4000-60000>
// Define the Timeout lower boundary for the WDT.
// Default: 4000
#define ClassB_TEST_POST_WDOG_WLB 4000


Using the minimum value of 4000 results in the system not meeting a maximum start-up delay time requirement. If I reduce the values of ClassB_TEST_POST_WDOG_WLB and ClassB_TEST_POST_WDOG_TIME to less than 4000, I am able to meet the start-up time requirement. It is unclear to me why 4000 is noted as the minimum value in the comments. The watchdog timer can be configured with lower values, and the test appears to be functioning correctly with a lower value.

Is it ok to use values lower than 4000 for ClassB_TEST_POST_WDOG_WLB? If not, what is the limitation?

I currently have it configured with these values, which seem to work fine:
#define ClassB_TEST_POST_WDOG_TIME      200
#define ClassB_TEST_POST_WDOG_WLB 100


Thanks!
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Travis
Employee
Employee
First solution authored Welcome! 500 replies posted
Hi Scott,

you can make use of the DAVE4 apps to re check on your WDT. Attached is a WDT project using XMC1200 for your reference.

Best Regards
Travis
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Hi Travis,

Thanks for the reply. I have the watchdog timer working, both for the POST test done by the Class B library on startup as well as during the normal operation of my code after the POST tests are complete.

My question is specifically about the Hitex Class B safety library WDT POST test. The comment in the library code (ClassB_config.h) indicates a minimum value of 4000 to be used as the minimum timeout value. I don't see anything in the documentation for the Class B safety library, or for the XMC1300, to indicate that 4000 is indeed a minimum limit for the timeout.

I have the watchdog POST test passing with a value <4000 as the watchdog timeout, but I'm looking for verification from someone that is familiar with the Class B safety library that my timeout value is ok for the test.

Do you know why the range of values for the watchdog timeout is specified as 4000-60000 in ClassB_config.h?
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Travis
Employee
Employee
First solution authored Welcome! 500 replies posted
Hi Scott,

Maybe you can discuss this with Hitex as they are the developer of the safety library.

Best Regards
Travis
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I heard back from Hitex that the settings I've used are ok.

The real limit is: ClassB_TEST_POST_WDOG_TIME > ClassB_TEST_POST_WDOG_WLB > 0
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