Converting a Blue Pill to a Black Magic Probe

This document shows how to convert a STM32F103 Blue Pill to a Black Magic Probe gdb server. A Black Magic Probe (BMP) allows you to download firmware over USB, to set breakpoints, and inspect variables.

A small note: If you have a STM32F103 blue pill, by all means use it. But if you are thinking of buying new, I suggest you buy a STM32F411 Black Pill and install Black Magic Probe for Black Pill. STM32F103 has 128kbyte flash, and after installing BMP flash is 89% full. This is getting tight. STM32F411 "black pill" has 512kbyte flash; this leaves much more room for future features. STM32F411 is a little bit faster, too.

Installing Firmware

Download blackmagic_bluepill.bin. Connect a STM32F103 Blue Pill for serial upload:

• Set boot jumpers for boot from rom: Boot0=1, Boot1=0.
• Connect a USB-Serial adapter with A9 to RX, A10 to TX.
• Press reset.
• Upload the firmware:

stm32flash -w  blackmagic_bluepill.bin /dev/ttyUSB0

with /dev/ttyUSB0 the USB-serial adapter

• Set boot jumpers for boot from flash: Boot0=0, Boot1=0.
• Press reset.
• Check the black magic probe shows up on usb:

$ lsusb
Bus 001 Device 044: ID 1d50:6018 OpenMoko, Inc. Black Magic Debug Probe (Application)

Creating Device Files

If you are running linux, download the udev rules for the BMP and install them in /etc/udev/rules.d/99-blackmagic.rules:

$ wget https://github.com/blacksphere/blackmagic/raw/master/driver/99-blackmagic.rules
$ sudo cp 99-blackmagic.rules /etc/udev/rules.d/
$ sudo chown root:root /etc/udev/rules.d/99-blackmagic.rules 
$ sudo chmod 644 /etc/udev/rules.d/99-blackmagic.rules 
$ sudo udevadm control --reload-rules

Disconnect and re-connect the BMP. Check the device shows up in /dev/:

$ ls -l /dev/ttyBmp*
lrwxrwxrwx 1 root root 7 Mar 24 11:59 /dev/ttyBmpGdb -> ttyACM0
lrwxrwxrwx 1 root root 7 Mar 24 11:59 /dev/ttyBmpTarg -> ttyACM1

Connecting to target

As target system we use another Blue Pill. Connect BMP and target like this:

If Black Magic Probe and target are both Blue Pills, connecting SWD and SWO looks like this:

Connect the Black Magic Probe USB to the Raspberry. Now we are ready to connect to the target system.

$ arm-none-eabi-gdb
(gdb) target extended-remote /dev/ttyBmpGdb
Remote debugging using /dev/ttyBmpGdb
(gdb) monitor swdp
Target voltage: unknown
Available Targets:
No. Att Driver
 1      STM32F1 medium density M3/M4
(gdb) attach 1

See the overview of useful gdb commands for an introduction to using the BMP.

stm32duino

If you are using the Arduino IDE with the stm32duino arm processor add-on:

In the Arduino IDE, choose Tools->Upload Method-> BMP (Black Magic Probe) to upload firmware using the BMP. This uploads the firmware using the arm-none-eabi-gdb command. The command line options to arm-none-eabi-gdb are in the tools.bmp_upload section of ~/.arduino15/packages/STMicroelectronics/hardware/stm32/2.0.0/platform.txt

When debugging arm processors, there are three ways for the target to print debug messages on the host: Semihosting, Serial Wire Output SWO, and Real-Time Transfer RTT. There are three Arduino libraries that may be useful:

• SerialWireOutput
• STM32duino-Semihosting
• RTTStream

See also

See the overview of useful gdb commands for an introduction to using the BMP.

If you want more in-depth information, read the Black Magic Probe Book.

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