/Circuitrocks_ISP4520_Bootloader

USB-enabled bootloaders for the ISP4520 SoC chips

Primary LanguageCMIT LicenseMIT

Circuitrocks Alora ISP4520 Bootloader

Thanks and credits for this bootloader are going to Adafruit.

This bootloader is based on the Adafruit_nRF52_Bootloader and adapted for the ISP4520 from Insight SIP.

The main reason why the orignal bootloader from Adafruit cannot be used is because of the integrated Semtech SX1262/1 LoRa transceiver chip that occupies some GPIOs that are used in the Adafruit bootloader.

This is a CDC/DFU bootloader for ISP4520 based boards.

adafruit-nrfutil, a modified version of Nordic nrfutil, is required to perform DFU. Install python3 if it is not installed already and run this command to install adafruit-nrfutil from PyPi:

$ pip3 install --user adafruit-nrfutil

This repository depends on the following submodules:

Note that tinyusb also includes nrfx as a submodule, so you need to initialize and update submodules with the `--recursive`` flag.

Clone this repo with following commands, or fork it for your own development

git clone https://github.com/beegee-tokyo/Circuitrocks_ISP4520_Bootloader
cd Circuitrocks_ISP4520_Bootloader
git submodule update --init --recursive

Features

  • DFU over Serial and OTA ( application, Bootloader+SD )
  • Self-upgradable via Serial and OTA
  • Auto-enter DFU briefly on startup for DTR auto-reset trick (832 only)

How to use

There are two pins, DFU and FRST that bootloader will check upon reset/power:

  • DFU = LOW and FRST = HIGH: Enter bootloader with CDC support
  • DFU = LOW and FRST = LOW: Enter bootloader with OTA, to upgrade with a mobile application such as Nordic nrfConnect/Toolbox
  • DFU = HIGH and FRST = LOW: Factory Reset mode: erase firmware application and its data
  • DFU = HIGH and FRST = HIGH: Go to application code if it is present, otherwise enter DFU mode
  • The GPREGRET register can also be set to force the bootloader can enter any of above modes (plus a CDC-only mode for Arduino). GPREGRET is set by the application before performing a soft reset.

On the Circuitrocks Alora ISP4520, DFU is connected to DFU button, and FRST is available as solderpad on the bottom of the board. So holding down DFU while clicking RESET will put the board into USB bootloader mode, with CDC support. Connecting FRST to ground and holding down DFU while clicking RESET will put the board into OTA (over-the-air) bootloader mode.

Burn & Upgrade with pre-built binaries

You can burn and/or upgrade the bootloader with either a J-link or DFU (serial) to a specific pre-built binary version without the hassle of installing a toolchain and compiling the code. This is preferred if you are not developing/customizing the bootloader. Pre-builtin binaries are available on GitHub releases

Note: The bootloader can be downgraded. Since the binary release is a merged version of of both bootloader and the Nordic SoftDevice, you can freely upgrade/downgrade to any version you like.

How to compile and build

You should only continue if you are looking to develop bootloader for your own. You must have have a J-Link available to "unbrick" your device.

Option 1: Build with Makefile

Prerequisites

To build:

make BOARD=alora_isp4520 all combinehex

To flash the bootloader with JLink:

make BOARD=alora_isp4520 flash

To upgrade the bootloader using DFU Serial via port /dev/ttyACM0

make BOARD=alora_isp4520 SERIAL=/dev/ttyACM0 dfu-flash

To flash SoftDevice (and chip erase):

make BOARD=alora_isp4520 sd

To erase all of flash:

make BOARD=alora_isp4520 erase

For the list of supported boards, run make without BOARD= :

$ make
You must provide a BOARD parameter with 'BOARD='
Supported boards are: alora_isp4520 feather_nrf52840_express feather_nrf52840_express pca10056
Makefile:90: *** BOARD not defined.  Stop

Common makefile problems

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

If you get the following error ...

$ make BOARD=alora_isp4520 all 
Compiling file: main.c
/bin/sh: /usr/bin/arm-none-eabi-gcc: No such file or directory
make: *** [_build/main.o] Error 127

... you may need to edit the Makefile and update 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 Nordic's nRF5x Command Line Tools.

3. make: nrfjprog: No such file or directory

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

On POSIX-type systems you can temporarily add the path to nrfjprog via a variation on the following command:

$ export PATH=$PATH:/location/of/nRF5x-Command-Line-Tools_9_7_2_OSX/nrfjprog

Option 2: Build using Segger Embedded Studio

For easier debugging you can also use SES. The project file is located at src/segger/Adafruit_nRF52_Bootloader.emProject.

Note: SES only flashes the bootloader when you click download, not the SoftDevice. You need to flash the SoftDevice beforehand if you haven't already done so. As mentioned above do something like:

make BOARD=alora_isp4520 sd