Progress towards getting the bootloader running on the nRF52840dk (PCA10056)

Useful guides:

• https://learn.adafruit.com/circuitpython-on-the-nrf52?view=all

1. Turn off the mass storage device jlink

2. Build the bootloader

   git clone https://github.com/adafruit/Adafruit_nRF52_Bootloader
   cd Adafruit_nRF52_Bootloader
   git submodule update --init --recursive
   make BOARD=pca10056 clean
   make BOARD=pca10056 sd
   make BOARD=pca10056 flash
   

3. Compile the kernel with flash address starting at 0x26000.

4. Convert a bin file to a DFU package

   adafruit-nrfutil dfu genpkg --sd-req 0xFFFE --dev-type 0x0052 --application target/thumbv7em-none-eabi/release/nrf52840dk.bin dfu-package.zip
   

5. Load the bin file

   adafruit-nrfutil --verbose dfu serial --package dfu-package.zip -p /dev/cu.usbmodem14201 -b 115200 --singlebank --touch 1200
   

Notes

• The bootloader appears to be at the top of the flash address range.
• This right now requires the softdevice to be included. If we only care about supporting the DFU version I'm not sure that is required.
• I had to remove the UICR erase step in the shared nrf boot code so that it does not clear the address of where the bootloader is. otherwise the softdevice does not jump to the bootloader.

from tock-bootloader.

I think with a little hacking it would be possible to make the bootloader DFU over serial only, and for it to not require a softdevice. And, the bootloader is only given 0xA000 bytes so it will fit in our standard 0x10000 space in flash.

from tock-bootloader.

Almost done in branch usb-cdc.

from tock-bootloader.

Done!

from tock-bootloader.