Debug Thread Examples with nRF52840 Dongle

[kalpino]

Hello,

I'm using CLI USB examble from Thread and Zigbee SDK by Nordic. I am using nRF52840 Dongle along with a J-link EDU mini.

My problem is that, when I start debugging by clicking the "Play" icon, the debugger does not stop at the first instruction in main. It goes somewhere in the disassembly.

The only way I found to debug Step-by-Step is to do a Full Erase of the Dongle before debugging. Unfortunately this cannot be a solution to my problem since the operation also erases the bootloader section in the Flash.

Can you help me solve this problem?

Thanks!

[Vidar Berg]

Hello,

Which bootloader is this? Most likely you will have to create a settings page with nrfutil to manually mark the application as valid for the bootloader. The bootloader will stay in DFU mode otherwise. Hung explains this in a bit more detail in this blog post (see appendix 1 at the end) https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader 

[kalpino]

I created a new hex file for the bootloader settings. I then merge this file with the bootloader found on the Nordic website (attached here). 

When I use nRF Connect to download the new bootloader hex file to the nRF52840 dongle I get an error saying the bootloader is not signed:

DFU failed: Error message for known extended error code from DFU target: The init packet does not contain a signature. This bootloader requires DFU updates to be signed.

What does it mean?

Thanks

3704.pca10059_bootloader.zip

[Vidar Berg]

Hi,

The update was rejected because it was not signed with your private key. Bootloader updates must always be signed even if you use the open bootloader. Have you generated your own key pair as explained in the blog post?

[kalpino]

Here's what I did.

Since I'm using SDK for Thread and Zigbee I used a new bootloader (not sure if it's the right one): SDK folder/examples/dfu/pca10056_s140_ble. I chose the s140 since my application is using dynamic multiprotocol.

I replaced the dfu_public_key.c with the one I previously generated.

I also replaced the board define to BOARD_PCA_10059 since I'm using dongles.

I rebuilt the project and merged the hex file with my bootloader settings hex file.

When I try to flash the resulting hex I get the error.

[Vidar Berg]

kalpino said:

When I try to flash the resulting hex I get the error.

 The error is reported from the existing bootloader when the Programmer app is trying to initiate DFU through the dongle's USB interface. Have you tried to flash it through the SWD interface with your J-link?

If you haven't seen it already, I recommend taking a look at this excellent tutorial on programming the 52840 dongle: https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/nrf52840-dongle-programming-tutorial

[kalpino]

I successfully flashed the new bootloader using J-link. Still, once I have flashed my app and the softdevice, the program remains stuck in the bootloader.

One question is: what is the cottect bootloader to use when using SDK for Thread? And what is the bootloader-version to use when creating the bootloader settings with nrfutil?

Also, I read something about setting BANK_VALID_APP = 0x01 in the bootloader using a specific hex file but the one I found changes flash line 0x3FC00 which is not part of the bootloader..

[Vidar Berg]

Hi, you need to generate and flash the bootloader settings page to inform the bootloader that a valid application exists. The setting of the BANK_VALID_APP flag approach was used with the old legacy bootloader (before SDK v12 and Thread SDK). 

kalpino said:

One question is: what is the cottect bootloader to use when using SDK for Thread?

 All variants are based on the same bootloader, but may have different transport layers and configuration settings. E.g., the bootloader that support DFU over thread is configured to allow DFU handling in the application. Follow the Thread Secure DFU protocol documentation if you want DFU over Thread, else you can take a look at the other DFU bootloader examples.