WDT in bootloader

RE: WDT in bootloader

Brian — Tue, 24 Nov 2015 01:10:31 GMT

Thank you Vidar! This solved my issue!

RE: WDT in bootloader

Vidar Berg — Mon, 23 Nov 2015 09:57:49 GMT

It will always be NRF_WDT->RR[0] = WDT_RR_RR_Reload; if you only allocated on channel in your application.

RE: WDT in bootloader

Brian — Fri, 20 Nov 2015 17:20:26 GMT

Good point! When I start the wdt in my app, I'm calling nrf_drv_wdt_channel_alloc and passing the address of an nrf_drv_wdt_channel_id variable. When I then execute sd_nvic_SystemReset() and my bootloader starts to execute, this variable has been reset. So what is the recommended way to maintain this data so that it is available in my bootloader following a reset? Even if I do maintain this value, haven't the values inside nrf_drv_wdt.c all been reset, such as m_state, m_alloc_index, etc. Is there any example code which maintains a watchdog timer across a reset event?

RE: WDT in bootloader

Vidar Berg — Fri, 20 Nov 2015 14:56:28 GMT

Are you sure that you are reloading the correct register in the bootloader? =>

NRF_WDT->RR[channel id] = WDT_RR_RR_Reload;

RE: WDT in bootloader

Brian — Thu, 19 Nov 2015 21:53:08 GMT

The board resets after about 2 seconds. I'm using the NRF_DRV_WDT_DEAFULT_CONFIG define to set up the wdt, which reload_value of 2000. I bumped this up to 5000, and now my board resets after about 5 seconds. So I'm certain that the wdt is causing the reset. As I said before, if I comment out my call in my app which sets up the wdt, everything works fine.

RE: WDT in bootloader

Vidar Berg — Thu, 19 Nov 2015 09:01:22 GMT

How long does it take before it resets? Note that the bootloader will reset itself after 2 minutes. You could try to increase the WDT timeout in your app as well to see if it makes any difference. Also, just to be sure, read the NRF_POWER->RESETREAS (nrf51 RM) on bootloader startup to verify that it was reset by WDT, and not an assert.

RE: WDT in bootloader

Brian — Wed, 18 Nov 2015 21:28:51 GMT

Thanks for the suggestions Vidar. My original code had a 500 ms timer to feed the watchdog. Even at 50 ms, I could see the LED flashing for several seconds which I was also toggling on the timer callback. I increased the timer frequency to 100 ms. I see the LED blinking faster now for several seconds, but then the board resets. I also added the code to feed the watchdog from wait_for_events(), but that didn't help either. Any idea why I'm unable to feed the watchdog in the bootloader?

RE: WDT in bootloader

Vidar Berg — Mon, 16 Nov 2015 08:22:22 GMT

The WDT keeps running in DFU mode as well as you've noticed. So it needs to be reloaded in the bootloader. So it seems like the wd_feed_timeout_handler() is not being called in time, or that the interval is too short.

Another alternative to creating an additional timer instance is to add nrf_drv_wdt_feed() function to the wait_for_events() loop in bootloader.c. Thus, WDT will be reloaded whenever an event has occurred. Just change the APP_ADV_TIMEOUT_IN_SECONDS to also get events when advertising openly (advertising will restart automaticcally on timeout events, so no actual timeout).