nRF52820 secure bootloader uart

[JoEi]

Hello,

we are trying to get the uart secure bootloader running on the nRF52820.
When linking we receive the error message that RTC1_IRQHandler is defined multiple times, once in bootloader_dfu_timer.o and once in app_timer.o.

We are using the SDK17.1.0

As far as I've seen the problem is that the nRF52820 only has 2 RTCs. RTC0 is used by the softdevice and now app_timer and bootloader_dfu_timer both try to use RTC1.

Has anyone successfully gotten the bootloader to run or at least to compile for the nRF52820?

[Vidar Berg]

Hello,

It's not possible to share the same RTC instance between these two implementations. That's why we only use the "dfu timers" in our example (lower memory footprint). Did you use one of the PCA10100E projects as a starting point?

Best regards,

Vidar

[JoEi]

Hi Vidar,

we use a bootloader that is based on the pca10056 examples, since we already use this one for other devices that use the nRF52840.

FYI: This bootloader was originally written with the SDK14.2.0 but has been ported to the SDK17.1.0

Best regards,
Johannes

[Vidar Berg]

Hi Johannes,

Maybe this is what you did already,  but I generally find that it's easier to start  with the project from the most recent SDK, then integrate the necessary modifications from your previous version, rather than trying to port a whole project from one SDK to another.

One approach could be to start with the 'pca10100e_usb' project and replace the USB transport with UART using 'pca10056_uart' as a reference.

Best regards,

Vidar

[JoEi]

Hi Vidar,

thanks for the fast response.
A colleague of mine ported the bootloader and it works for our nRF52840 devices.

I just had a quick look through the new pca10056_uart example and I've noticed that it doesn't use the app_timer.
Just a quick thought of mine but could it be enough to just remove the app_timer from the bootloader?

Best regards,
Johannes

[Vidar Berg]

Hi Johannes,

Yes I think so. Our example does not rely on the app timer library at least. You can of course make sure yours doesn't either by searching through it and  see if any of the app timer functions are being used or not.

Best regards,

Vidar

[JoEi]

Hi Vidar,

thanks, that would be awesome. =)
I'll try it and let you know if it worked.

Best regards,
Johannes

[JoEi]

Hi Vidar,

as expected the app timer wasn't needed.
After removing it, everything worked fine.

Best regards,
Johannes