freertos with wdt reset problem, nrfjprog

[twittich]

Hello

my setup is a nrf52840, the sdk15.3, Softdevice s140.

I'm running an application with freertos and wdt and have the openbootloader and s140 also flashed.

- if in freertos the wdt is disabled and i set the GPREGRET register and make a reset with NVIC_SystemReset, i have to make a reset from outside by nrfjprog -r over jlink and then the dfu device comes up...

- and after update the device over dfu it has to be reset by nrfjprog -r and it resetarts in application as wanted

- If the wdt is enabled and do the same, set the GPREGRET register and make a reset with NVIC_SystemReset, the device restarts in application....

How can i make a reset or restart similar to nrfjprog -r from software so that no jlink is needed ?

Thanks in advance

twittich

[Vidar Berg]

Hello Twittich,

The WD timer is not reset through a NVIC_SystemReset (Reset behavior) so it will keep running on subsequent startup when the program enters DFU mode inside the bootloader.  The bootloader feeds the WD by default for this reason. But you may need to adjust the reload interval if you have a short timeout, see NRF_BL_WDT_MAX_SCHEDULER_LATENCY_MS in the bootloader's sdk_config.h file. 

[twittich]

Hello

Thank you. This i tested already but it's still the same. While debugging the bootloader at the function

static bool dfu_enter_check(void)

it's not entering in the following

   if (NRF_BL_DFU_ENTER_METHOD_GPREGRET &&
       (nrf_power_gpregret_get() & BOOTLOADER_DFU_START))
    {
        NRF_LOG_DEBUG("DFU mode requested via GPREGRET.");
        return true;
    }

the problem is at

nrf_power_gpregret_get()

i'm not getting 0xb1 .  If I set this hardcoded to 0xb1 it's starting in dfu mode.....

But in the application i'm setting it and then make a reset.

Can I use the sd functions ?

sd_power_gpregret_set(0,0xB1);
sd_nvic_SystemReset();

Or use the GPREGRET2 and change that in the application and bootloader ?

And regarding the reset of the device after the dfu and update, any idea ?

Thank you for any help....

twittich

[Vidar Berg]

Hello,

The retention register will be read as zero if you have a WD reset occurring before the bootloader has had time to read back the flag. So could it be possible that you get a timeout? As a test, can you increase the reload interval when you initialize it in the app to >5 seconds and see if you get the same result? What is your current timeout?   

[twittich]

Yes i had set it already to 15 and 30 secs but still no difference, the timeout which should be used in future is 1.5 sec if possible.
Do you mean when i make a wd reset (feed the dog) the register is affected or when the wd time out?

[Vidar Berg]

I meant to say that the retention register will be reset if you let the WD timer time out (i.e., not reloaded in time). I'm not sure why you still see this with a timeout of 15-30 seconds though. Can you check the RESETREAS register in the bootloader on startup and see if the 'Reset from watchdog detected' bit is set? 

[twittich]

Ok, i thought so. I'm one step further.

Vidar Berg said:

The bootloader feeds the WD by default for this reason

The bootloader isn't feeding the WD, the device stays in the bootloader and is waiting to start the update process ( the inactivity timeout is set to 0 ) until the wd timeout . If i start the update process then it's feeded and the update proceeds as normal.

But it's strange that i have to make a reset over "nrfjprog -r" then the dfu device comes up. There is no difference if i use "NVIC_SystemReset();" or "sd_nvic_SystemReset();"

Can the function "nrfjprog -r" be reconstructed by software?