SDK/Peripheral/UART not working.

[kunal]

I recently was trying to test my nrf52 DK. After lot of failed attempts i was able to do DFU update over BLE and also Serial upload .

I am now trying to test the BLE UART application. which does not work at all.

Please correct my understanding

1. The nrf52 in DK had a bootloader in intial state and after I flashed my DFU bootloader, the factory one was deleted. is it true?

2. During testing DFU update of an BLINKY_application i realised that for every update of ' BLINKY_application' i have to use the same application code used for generating bootloader settings, because the Bootloader Settings uses a crc and this crc is unique for each new application. And to Change to other example application Code (e.g. UART, HRM etc)i have to Change the bootloader Settings first. is it right??

3. After the DFU bootloader is flashed if i now want to test a completely new application example Peripheral/UART example. I have to again generate new bootloader Settings file. True?

4. what if i completely erase the chip so as to delete the DFU bootloader completely and now Flash the SOftdevice and then the Peripheral/ UART example ? it should work right?

Or i have a completely wrong understanding. please guide.

[bjorn-spockeli]

Hi Kunal,

Q1: No, our nRF52 DKs does not come with a bootloader pre-programmed from the factory, the flash is entirely erased when you receive it.

Q2: You only have to generate the bootloader settings page the first time you flash the bootloader, application and SoftDevice to your device using a programmer or the nRF52 DK JLink OB. After the initial flash you can update the application using Over-the-air DFU or Serial DFU. The bootloader settings page will be updated after each update. However, if you want to flash a new application (i.e. not create a firmware image everytime you recompile your application) to your nRF52 DK via the J-LINK OB programmer, then you have to create a new bootloader settings page for each "new" application.

Q3: Yes, if you flash the new application using a programmer, i.e. you do not create a firmware image using nrfutil and update the application via DFU(BLE or serial), then you must create a new bootloader settings page.

Q4: Yes, a nRF52 device will jump directly to the application if there is no bootloader present on the device.