RTT Log with MCUBoot

[thang47]

Hi,

I have a problem with nRF52840 module.

In my config, when I disabled CONFIG_BOOTLOADER_MCUBOOT=n, Then my circuit runs normally and prints out the log via RTT J Link.

But when I enabled CONFIG_BOOTLOADER_MCUBOOT=y, Then my circuit does not run and does not print any log.

My program run with toggle the led pin0.20.

I'm using nRF Connect SDK v2.4.0

[Einar Thorsrud]

Hi,

Is the problem here that you don't get RTT logs from the application when you have RTT logging enabled in MCUBoot? If so it could be that you are seeing a quite common issue, which is related to how the RTT viewer works. By default, it will search for the RTT buffer in memory, and stick with the first it finds. And the bootloader and application will typically not place the RTT buffer at the same location. In that case, you could manually specify where the buffer is as suggested in this post.

[thang47]

Hi,

But in my case the chip doesn't run after I add mcuboot configuration

[Einar Thorsrud]

Ah, I see. I focused on the RTT logging and did not notice that that was just a way you observed if the app was running, and that the difference was in adding MCUBoot.

A few questions to understand more

1. Did you program both MCUBoot and the signed application after having built the project with MCUBoot? (If so, the app should have started.)
2. Did you do any other changes?
3. Did you get any error or warnings when building or flashing?
4. How did you flash?
5. Have you done any debugging and what have you found out? What exactly does happen when you write "the chip doesn't run"? You could 

[thang47]

Hi,

My problem like the ticket: devzone.nordicsemi.com/.../enabling-mcuboot-does-not-run-application

[thang47]

I made 1 led blinking, but when I add the MCUboot configuration, the led no longer blinks.
I used J Flash and the project's hex file to load the nrf52840 module

[Einar Thorsrud]

Can you elaborate more? Which exact hex file did you flash? (you need to flash both MCUboot and the signed application, or a merged hex file that includes both, which is simplest. This is called merge.hex. Is that what you flashed?

[thang47]

Hi,

Thank you, I flashed the wrong hex file, it should be merg.hex but I used MCUboot to DFU, which hex file to use for OTA. I tried the app_update file but it didn't work.

[Einar Thorsrud]

Hi,

The file you use to update the application via DFU is app_update.bin.