what is WDT, how to use it?

Guest · Posted: Thu Jul 29, 2004 7:43 am

Could anyone explain to me what is WDT, and in what situation can i use it, and how to use it?

Mark · Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA

Watchdog timer. It can reset your processor if your code goes "into the weeds". Look up the section in the datasheet for a better explaination.

valemike · Guest

If you have no serious mistakes in your code, you probably won't need the watchdog timer while in the lab.

However, if you try to get UL to approve it, they will throw all kinds of noise, voltage spikes, etc. onto your circuit to see if it will withstand or recover from it. That is when your code can go haywire. So you'll need to turn on your watchdog timer. Also, as i've learned from some in-house testing with some test tools we rented, I found that if you spike your incoming voltage very quickly, not even the watchdog can recover your circuit. For such a thing, you'll need to enable your "Power-up Timer" (PUT) on the PIC. Why, i don't know.

-Mike

arunb · Joined: 08 Sep 2003 Posts: 492 Location: India

Hello,

In my firm I am responsible for designing software and also testing them thoroughly before sending them to the customer for installation.

We usually reduce the primary AC voltage to see the behaviour of the PIC in brownout conditions, but this test is not complete in all respects. ( I use the Power up timer , brownout detect, and the WDT in all my projects).

I would like to do all the tests you mentioned previously, can you please explain in detail how I can reproduce them in my lab.

thank you
arun