Flashing nRF with OpenOCD ST Link

Some nRF chips in a small form factor need to be flashed manually. Either by using a J-Link (which can be expensive) or a cheaper ST-Link in combination with openocd.

Steps

1. Install openOCD

2. Connect the pins to the correct ST-Link pins. A sample schematic of an nRF52 Beacon can be found below

3. Build your firmware with the correct keys

4. Run openocd with the correct configuration

   openocd -f share/openocd/scripts/interface/stlink.cfg -f share/openocd/scripts/target/nrf52.cfg

   The first parameter here uses the configuration file for the connected interface (stlink-v2) and the second parameter loads the config file for the nrf52 boards

5. Now openocd is running. You can connect to it using telnet:

   telnet localhost 4444

5.1 You can get all available commands using the help command 6. Stop the execution with halt 7. You can backup the existing firmware: bash dump_image /Your/File/Path/flash.bin 0 0x40000` 8. Erase the flash using

 nrf5 mass_erase