How to make it run application when there is a bootloader in the nRF52

[Alice]

Hi,

I'm using the bootloader in nRF5_SDK V12.0 with nRF52832. I have some problems want to know:

1. How to make it run application first after I program softdevice,bootloader and application? I found that it runs the bootloader and broadcast as "DfuTarg". I know it can set m_boot_settings in nRF5_SDK V11.

2. After I finish the OTA, it can run the application. However, if I just do a little modification in my application and then program it, it would neve run the application,it runs the bootloader. Is it normal?

3. I want to use AT command received by the UART to make it switch to bootloader instead of using a button. I do that like this: In my application,when received the AT command, I will write a value to the flash(the last page in the flash) using fstorage then do a reset. In the bootloader, I add some code to read the flash to check the value. So my question is I should use the fstorage or do it like flashwrite example in SDK? Which way would you suggest? Thanks.

[bjorn-spockeli]

Hi Alice,

1. You have to generate the bootloader settings page that sets the application crc and the bank 0 status flag to NRF_DFU_BANK_VALID_APP, see this page in the nrfutil documentation.
2. The bootloader will check the CRC of the application against the application CRC stored in the bootloader settings page. If you flash a new application to your device, then the CRCs will not match. Thus, you have to update the bootloader settings page that corresponds to your new application.
3. If you're only writing one value to flash then I suggest that you use the SoftDevice Flash API, see sd_flash_write documentation in the S132 SoftDevice API documentation.

Best regards

Bjørn

[bjorn-spockeli]

The bootloader will calculate the CRC of the application and compare it to the CRC that is stored on the bootloader settings page(@0x7F000) that you created with nrfutil and merged with your bootloader, Softdevice and application hex. The settings page that you attached above shows that nrfutil calculated the CRC to 0x5BA4336D. If you have flashed the same application to your nRF52, then crc32_compute in nrf_dfu_app_is_valid should return the same crc, if it doesn't then its not the same application. Can you set a breakpoint at the if (crc != s_dfu_settings.bank_0.image_crc) statement and see what crc32_compute returns?