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If the watchdog (WDT) function is enabled in the config bit, will it affect ISP upgrade procedure?

Posted: 29 Mar 2017, 10:47
by AlsoJoe
If the watchdog (WDT) function is enabled in the config bit, the watchdog will start automatically. The default clock source is internal low speed 10 kHz clock. Reset Time = Overflow Time + Delay Time
= (2 ^ 18 + 1026) /10k=26.3 seconds.

The Nuvoton ISP Boot Loader program did not include the watchdog function. If the watchdog (WDT) function is enabled in the config bit and the ISP upgrade time is more than 26.3 seconds, there will be a watchdog reset, and ISP upgrade will fail.

Therefore, if the user needs to enable the watchdog (WDT) function in the config bit when using the Nuvoton ISP Boot Loader, please be sure to add the watchdog reset function to the ISP Boot Loader; otherwise, when the ISP operation time is more than 26.3 seconds, because the upgrade time is too long, more than a watchdog reset time, it will cause chip reset and ISP upgrade failed.