Go to bootloader on PCA10059 with CDC connectivity software (without Reset button)

[Gaétan]

I use nrfutil.exe in Windows command line with a nRF52840 PCA10059 dongle to update slaves devices in BLE.

To do this, I replace my proprietary firmware by the connectivity_4.1.1_usb_with_s132_5.1.0.hex program in the dongle.

All this works perfectly.

However, I have a problem when I want to reload my proprietary firmware into the dongle. Because for nrfutil.exe to work, the dongle must be in bootloader mode (red led flickering).

Is there an option in nrfutil.exe to force the PCA10059 to switch to bootloader ?

My question is how to make via the comm CDC (without using the Reset button) to pass the dongle in mode bootloader when this one run the connectivity firmware ? 

I know it's possible because if I use the graphical interface of nrf connect I can do it.

My concern is to automate (command line) all these tasks and therefore it is not possible to use nRF Connect !

Regards,

Gaétan

[Hung Bui]

Hi Gaetan, 

There's actually multiple option you can do to put the device to DFU mode: 

- Trigger a pin reset by using a GPIO. This is actually what we do in our PCA10059. We connect one GPIO pin (P0.19) to the reset pin on the board. In the firmware we will active this pin when we receive the command from the PC. This will trigger a pin reset and the bootloader will enter DFU mode when there is a pin reset (equivalent to press SW2 on the dongle). You can have a look at this library. You can write your own library as well. Just need to have your code on the PCA10059 to toggle the GPIO pin. 

- Write to GPREGRET retention register and reset. You can write your code so that when it receive a command it will write to GPREGRET a flag and in the bootloader, it will be checked and the bootloader will enter DFU mode. Please have a look at our buttonless example. 

The challenge here is that as far as I know nrfutil wouldn't do a request to switch to DFU and expect the board in DFU bootloader. So you may need to write your own application on PC to do so and then use nrfutil to do DFU. 

[Gaétan]

I think I wasn't very clear.

When the PCA10059 runs the connectivy firmware, I would like to be able to send it a new firmware via nrfutil.exe.

Unfortunately, for the nrfutil.exe command to work it seems that the dongle has to be in bootloader mode (red LED).

My question is: what solution can I use to force the connectivy firmware (the original one) to launch the bootloader?

Maybe there is a parameter to add to the nrfutil command line to force the connectivity firmware to bootloader?

Maybe there is a frame to send on the CDC port to force the connectrivity firmware to launch the bootloader?

Regards,
Gaétan

[Hung Bui]

Hi Gaetan, 
It's possible for the nrfutil.exe to put the application to DFU mode (I was not correct in the previous answer). nrfutil does this automatically. But your application need to support DFU trigger protocol as I pointed to earlier. 

One example of a firmware that supports the protocol is the firmware for nRF Connect for Desktop - Bluetooth Low Energy application.
You can test this by putting the dongle to DFU mode, then open the dongle in nRF Connect for Desktop -> Bluetooth Low Energy application. After that Bluetooth Low Energy application will ask to flash the dongle with the BLE backend firmware:

After you flash the firmware, it will run as a BLE emulator. 

At this point you can use nrfutil.exe to do a DFU and the application will automatic switch to DFU mode. You will notice that the red LED will start after you enter DFU command in nrfutil.exe
The way it switches to DFU mode is what I described at point #1 in my last reply, by triggering a pin reset. 

So what you need to do is to implement the DFU trigger library in your application allowing it to detect the command from nrfutil.exe.