WDT not firing

RE: WDT not firing

Stefan Birnir Sverrisson — Fri, 28 Aug 2015 18:07:02 GMT

Hi Lee

Ok, good that you spotted that this is a first revision nRF51. Then I am not surprized that not everything is working with SDK 8.1.0. You should get third revision instead.

RE: WDT not firing

Lee Daniel Crocker — Thu, 27 Aug 2015 16:39:23 GMT

According to the HWID (0x002F) it looks like a revision 1 chip. Compatibility matrix says I should be using SDK 4.4.2 and SD 5.2.1. I'll have to look into where we're getting those chips.

RE: WDT not firing

Stefan Birnir Sverrisson — Thu, 27 Aug 2015 12:43:18 GMT

If you have second revision nRF51, you might be better off by trying these examples. They are made for SDK 5.2.0 which is compatible with second revision.

I see there is one PAN anomaly #48 which was fixed for third revision nrf51, so SDK 8.1.0 might not implement the workaround for anomaly #48

RE: WDT not firing

Stefan Birnir Sverrisson — Thu, 27 Aug 2015 12:37:12 GMT

Hi Lee

The chip is in debug mode after you flash the code. After you power reset it will go into normal mode.

There are some pan issues for the WDT in the PAN but I do not see them directly map to your situation. The nRF51822 CEAA could anyway be both second or third revision. What are the full chip markings on your nRF51 chip, is it second or third revision? The nRF51 SDK 8.1.0 is not compatible with the second revision, see the nRF51 Compatibility matrix. So if you have the second revision hardware and use it with SDK 8.1.0, that might be an issue.

RE: WDT not firing

Lee Daniel Crocker — Wed, 26 Aug 2015 17:37:22 GMT

The examples unfortunately run only on demo boards I don't have. I've noticed now that the watchdog does fire after some kinds of restart, but not immediately after programming. So I'll have to figure out how that lines up with conditions of my device in the field.

RE: WDT not firing

Stefan Birnir Sverrisson — Wed, 26 Aug 2015 06:54:34 GMT

I can't quickly see anything else you are missing, but clearly there is something that is making your code not work. Try to start with the original example and gradually modify it, one step at a time, until you have your own code. Then perhaps you will find out in which step it stopped working and realize what the problem is.

RE: WDT not firing

Lee Daniel Crocker — Mon, 24 Aug 2015 16:39:51 GMT

That's the code I copied from. The comment on that line says it's for the button timer used to feed the watchdog, so I left it out deliberately. Putting it back in doesn't fix the problem: watchdog still never fires, but thanks for the suggestion. I'll look around in that code for other things I might have left out.

RE: WDT not firing

Stefan Birnir Sverrisson — Mon, 24 Aug 2015 16:09:12 GMT

Hi Lee

Have you seen the WDT example in the nRF51 SDK? I suspect you are missing to initialize the low frequency clock, which the WDT requires. Something like

nrf_drv_clock_init(NULL);