Firmware Hacking

The Black Magic Debug firmware is under the GPLv3 open-source license, all contributions to the project should be either GPLv3 or compatible.

Any contributed hardware designs found in the hardware repository is under the CC-BY-SA license.

Getting the project source

The project resides in a GitHub git repository

Clone this repository (or fork and clone) using your desired method. Typically:

git clone --recursive https://github.com/blackmagic-debug/blackmagic.git

The project uses libopencm3, which is included as a git submodule. If you don’t provide the --recursive parameter above you will have to initialize and check out locm3 as a submodule:

cd /path/to/blackmagic
git submodule init
git submodule update

Compiling for the native hardware

To build the firmware for the standard hardware platform run make in the top-level directory. You will require a GCC cross compiler for ARM Cortex-M3 targets. A good option is gcc-arm-embedded. The default makefile assumes the target prefix is arm-none-eabi-. Then only

make

is needded. If your compilers uses some other prefix, you can override this on the command line like e.g.:

make CROSS_COMPILE=arm-cortexm3-eabi-

This will result in the following binary files:

  • blackmagic.elf - ELF binary of the Black Magic debug probe.

  • blackmagic.bin - Flat binary of the Black Magic debug probe, load at 0x8002000.

  • blackmagic_dfu - ELF binary of the Black Magic DFU bootloader.

  • blackmagic_dfu.bin - Flat binary of the DFU bootloader, load at 0x8000000.

Alternative Hardware

A number of users have contributed alternative hardware designs that are compatible with the native firmware. Some of these designs are in the hardware repo. Check the README.md files for details. For instance, to compile a BMP for an ST-Link v2 to run as alternative to the ST firmware, compile:

make PROBE_HOST=stlink ST_BOOTLOADER=1

then replug the STLink to get into the bootloader and load with [stlink-tools] (https://github.com/jeanthom/stlink-tool)

stlink-tools blackmagic.bin

Building on Windows

Sid Price wrote a detailed step by step guide describing how to set up CygWin and compile the Black Magic Probe firmware.

Compiling as a PC application

The Black Magic application can also be compiled as a native PC application. Supported probes are BMP (with recent firmware), ST-Link v2/v3, FTDI-MPSSE probes, JLink and CMSIS-DAP.

Compile the application with the command:

make PROBE_HOST=hosted

Enabling DEBUG() messages

Easiest way is to compile a PC-hosted BMP. Run blackmagic -v 1 so that all infos are printed on the controlling terminal. Argument to -v is a bitmask, with -v 31 very verbose. If you do not succeed in compiling PC-hosted, use following steps as a last resort to compile in the debug messages when building the firmware:

make ENABLE_DEBUG=1

Then enable debug messages in gdb with the new command

monitor debug_bmp enable

The debug messages appear on the debug UART. On a BMP the USB UART device is used.

screen /dev/ttyACM2 115200

Exit the screen session by type crt-a + ctl-.

Updating firmware

Follow instructions in Firmware Upgrade Section.

Checks before providing pull requests

Before providing a pull request, please check and remove trailing whitespace: git rebase –whitespace=fix … Test that all platforms compile: cd src; make all_platforms. As long as your patch request is not applied and you detect an error or omission in an earlier step not yet applied, consider rewriting the history (git rebase -i …) to correct in the first place and not adding the correction as a patch on top.