Watchdog Options

#1

I am making good progress on a few of my projects and I am pondering the next steps on the vault hardware. Once I get a solid program complete, and that is getting really close, I want to design a project specific board for the controller. I am at a crossroads of unknown direction in watchdog timer options. I have seen some references to watchdog code to be dropped in to a sketch and have seen hardware watchdog elements as well. As a matter of fact, Jon sells one here on Superhouse I could integrate. Being as I am looking at creating an all in one board design though, I think I would probably want to integrate that into my board instead of an add-on. I am leaning towards hardware based timer. The reason being, since I don’t have any experience with this stuff, I would believe that if your processor hangs up, your software based timer is gonna hang too?

Anyone with experience that wants to kick in some thought on this?

#2

Hey mate, have watched Johnathan’s episode #15? Explains it pretty well around the 8:00 min marks pretty much explains your question?

Hope this helps
MS

#3

LOL. Yeah, I have seen all of them. Many times. But I keep forgetting what was in there. Guess it’s time to binge watch them again.

#4

The circuit for the hardware watchdog is quite simple, so incorporating it into your design should be fairly easy.

However, a word of warning about a trap that I fell into when I first implemented a hardware watchdog: you need a way to disable it for development. It’s really annoying to have a watchdog that hits reset on your microcontroller just when you’re in the middle of uploading new code and it’s not executing its watchdog reset code!

That was a head-slap moment when it first happened to me.

So in your design, put a 2-pin header with a jumper (or a cut-track if you prefer) between reset and the watchdog output, so that you can disable it while you’re doing software development.

3 Likes