secure_bootloader pca10056_uart

[Jukka Lamminmaki]

Hi,

We are evaluating devkit nRF52840-DK using SDK nRF5_SDK_16.0.0_98a08e2.

The application development is ongoing, based on examples\ble_central, using which we are able to listen to beacons and report them to UART.

Next phase is to test the bootloader, which I built using the help of Getting started with Nordic's Secure DFU bootloader, a step by step guide page. Assumption was, that building the examples\dfu\secure_bootloader\pca10056_uart would give us possibility to download the application via the same serial port as used by the application, using e.g. the nRF Connect Programmer -tool.

However the bootloader doesn't start the application already existing in the flash, it only burns the LED1 and LED3 green. Neither does the Programmer tool recognize the bootloader if trying to connect to it via the PC serial port.

There seems to be something that we are missing here. Shouldn't the bootloader:

- always automatically start the application, if one is found in FLASH? Security keys shouldn't affect this, they matter only on DFU-process

- connect to PC via UART (P0.06, P0.08) if xxx_uart revision is built? Is the nRF Connect Programmer correct tool for this?

Regards, Jukka

[Vidar Berg]

Hi Jukka,

You need to make a valid bootloader settings page as Hung explains at the end of the blog post under: "Combine application, bootloader, bootloader setting and softdevice image" if you're programming the app through the debug interface. Otherwise, the bootloader will not know if you have a valid application in bank 0 or not, and thus fall back to DFU mode (indicated by LED1 and LED3 being lit).

connect to PC via UART (P0.06, P0.08) if xxx_uart revision is built? Is the nRF Connect Programmer correct tool for this?

The onboard Segger chip includes VCOM support (USB to UART bridge) and is connected to these UART pins by default so you shouldn't have to make any connections.  Have you connected the UART pins to another USB bridge? That may not be supported by nRF connect. 

Regards,

Vidar