How to make Watchdog timer(WDT) of PSoC4000 not be stopped by software?

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Anonymous
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I have 2 question about PSOC4000 WDT (CY8C4014SXA-421Z)

1- WDT is reset/stop by both software and hardware, right?

2- If 1- is right, how to disable the function that reset/stop WDT from software?

Regards,

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RyanZhao
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1- is right.

WDT won't be reset and stopped if there is no command/hardware to reset/stop it. However, two unserviced WDT interrupts will lead to a system reset (i.e. at the third match). Suggest to clear the WDT interrupt in its interrupt handler.

Here is a KBA described details about how to use PSoC4000 WDT. FYI.

Watchdog Timer in the PSoC® 4000 Family – KBA91373

Thanks,

Ryan

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RyanZhao
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1- is right.

WDT won't be reset and stopped if there is no command/hardware to reset/stop it. However, two unserviced WDT interrupts will lead to a system reset (i.e. at the third match). Suggest to clear the WDT interrupt in its interrupt handler.

Here is a KBA described details about how to use PSoC4000 WDT. FYI.

Watchdog Timer in the PSoC® 4000 Family – KBA91373

Thanks,

Ryan

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Anonymous
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Hi Ryan,

Thank you for your answer.

I've confirm the TRM P.74 and see that it's possible to disable the watchdog reset by writing a key '0xACED8865' to the WDT_DISABLE_KEY register

http://www.cypress.com/file/126386/download

So, in case the software write '0xACED8865' to the WDT_DISABLE_KEY register while WDT_COUNTER is counting and not reached WDT_MATCH by the 3rd time (to generate a hardware reset), what will happen?

(should WDT_COUNTER be stopped and the program get stuck in the WDT_COUNTER routine without reset? )

I do not expect that the program/software going to stop WDT by any cases. 

Best Regards,

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RyanZhao
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Hi Nam Son Tran,

In that case, wdt will free run, and system reset won't generate.

Thanks,

Ryan

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