Taranis Hardware Debugging

The Hardware you'll need

• This board: STM32F4 DISCOVERY USB STM32F407VGT6 STM32 ARM Cortex-M4 Development Board (you will find it on eBay)
• These 1.25 plugs: Mini. Micro 1.25 T-1 4-Pin JST Connector w/.Wire x 10 sets (you will also find them on ebay)
• One 100 Ohms SMD resistor
• One JWT 4 pins connector (I got them from HobbyKing)
• The mini USB cable (the one you use to flash your radio everyday)

The Software you'll need

• STM32 ST-LINK utility with the associated driver (here)
• OpenOCD 0.7.0 (André prepared a beautiful zip for us here)
• The GCC ARM toolchain (here)

Preparation

• Solder the 100 Ohm resistor on the empty R2 slot of the discovery board (next to the SWD connector)
• Solder the mini JST plug on the Taranis board here:
• Prepare your cable according to this schema:
  • JTMS -> SWDIO
  • JTCK -> SWCLK
  • GND -> GND
  • VCC -> VDD

Installation

• Install the STM32 ST-LINK utility, it will automatically install the driver for the board
• Plug the board through the mini-usb cable. The board will be detected and the driver correctly setup
• Start the STM32 ST-LINK utility, go in the ST-LINK menu and choose Firmware Update. Check that the board is correctly detected and start the update.

Start the debugging

• Connect everything
• Start a cmd window and launch OpenOCD with this script:

openocd-stlinkv2.bat

• Start another cmd window, go inside the OpenTX src directory and launch gdb this way:

"C:\Program Files (x86)\GNU Tools ARM Embedded\4.7 2013q3\bin\arm-none-eabi-gdb.exe" opentx.elf

• Now inside gdb:

target remote :3333  
monitor reset  
break perMain  
cont

The program should stop in perMain

set unexpectedShutdown = 1  
cont

You should now see the asterisk in the notification bar

set unexpectedShutdown = 0  
cont

The asterisk should be removed now!

Enjoy!