Adafruit nRF52840 Bootloader

This repository contains the USB bootloader for Adafruit nRF52840 boards (1MB flash, 256KB SRAM). This repository depend on the tinyusb as submodule, after cloing this repo you need to run this command

git submodule update --init

Option 1: Build with makefile

Navigate to src/singlebank (recommended) or src/dualbank (work in progress), and use feather52840 target for building bootloader.

make feather52840

To flash bootloader + S140

make flash_feather52840

To only flash S140

make flash_sd

Common makefile problems

1. arm-none-eabi-gcc: No such file or directory

If you get the following error:

$ make feather52840
Compiling file: dfu_single_bank.c
/bin/sh: /usr/bin/arm-none-eabi-gcc: No such file or directory
make: *** [_build/dfu_single_bank.o] Error 127

You make need to edit the Makefile (for example src/singlebank/Makefile), and update the GNU_INSTALL_ROOT to point to the root path of your GCC ARM toolchain.

2. mergehex: No such file or directory

Make sure that mergehex is available from the command-line. This binary is part of of Nordic's nRF5x Command Line Tools.

Option 2: Build using Segger Embeded Studio

For better debugging you can also use SES, The project file is located at src/segger/nrf52840_bootloader.emProject. Note: the SES only flash the bootloader when you click download, you need to flash Softdevice beforehand if you haven't done so ( use make flash_sd mentioned above )