lukeore / nrf52-blinky-demo

Example project to flash/debug firmware using Visual Studio Code.

nRF52 Blinky Demo with Visual Studio Code

Example project to setup, flash, and debug nRF52 firmware using Visual Studio Code.

The Nordic toolchain is cross-platform, but the instructions below are specifically for Linux. However, they can easily be replicated in Windows as long as installation paths and environment variables are set correctly.

General Comments

When using any editor + terminal for nRF52 development, the things to remember are:

• GCC path is set in <sdk>/components/toolchain/gcc/Makefile.posix
• Makefile is up to date with:
  • SDK_ROOT is pointed to where <sdk> is located
  • Source and header files for new components
  • Board/component configurations in sdk_config.h

With Visual Studio Code:

• In .vscode/c_cpp_properties.json, update defines, includePath, and compilerPath as required
• In .vscode/launch.json, update executable and armToolchainPath as required
• In .vscode/tasks.json, update the current working directory cwd and command as required (ie. changing to make flash -j8 to use 8 cores to build).

Screencap of Visual Studio Code using the Cortex-Debug extension.

Installation

System Tools

sudo apt install build-essential

# Required by java-based CMSIS Configuration Wizard
sudo apt install default-jre

Code Editor

• Visual Studio Code
  • C/C++ Extension by Microsoft
  • Cortex-Debug Extension by marus25

nRF52 Toolchain

Download

1. nRF52 SDK
2. nRF52 Command Line Tools
3. Segger J-Link Software Tools
4. GNU-RM Embedded Toolchain for ARM
   • It's recommended to install the GCC version that matches the Nordic SDK version. Check the GCC version in <sdk>/components/toolchain/gcc/Makefile.posix and download the appropriate version.
   • For nRF5 SDK 15.3.0, the gcc version is gcc-arm-none-eabi-7-2018-q2-update

Optional:

1. Segger Ozone Debugger

Setup

Run the commands below to extract the archives to the respective paths.

• nRF5_SDK to $HOME
• nRF Command Line Tools to /opt/ and /usr/local/bin
• gcc-arm-none-eabi to /usr/local/bin

# Unpack SDK to home directory
unzip nRF5_SDK_15.3.0_59ac345.zip -d $HOME

# Unpack nRF command line tools and make accessible in terminal
tar -xvf nRF-Command-Line-Tools_9_8_1_Linux-x86_64.tar --directory /opt/
sudo ln -s /opt/nrfjprog/nrfjprog /usr/local/bin/nrfjprog

# Install Segger
sudo apt install ./JLink_Linux_V644f_x86_64.deb

# Unpack gcc toolchain to /usr/local/bin
sudo tar -xjvf gcc-arm-none-eabi-8-2018-q4-major-linux.tar.bz2 --directory /usr/local/bin

If optional tools are downloaded:

# Segger Ozone
sudo apt install ./Ozone_Linux_V262_x86_64.deb

Check nrfjproj --version that it's been installed correctly.

Nordic SDK Setup

In the nRF52 SDK folder, update the values in components/toolchain/gcc/Makefile.posix:

• GNU_INSTALL_ROOT
• GNU_VERSION

This is only required if using a different gcc version than specified. It's recommended to use the same one as the SDK.

Using the Project

Setup

In blinky/ directory, do a global search and replace to update the SDK root to wherever your nRF5_SDK directory is:

• From: SDK_ROOT := ../../../../../..
• To: SDK_ROOT := $(HOME)/nRF5_SDK_15.3.0_59ac345

If required, update the following in .vscode/c_cpp_properties.json:

• Include paths
• Defines based on C/assembler flags in the Makefile

Configuring sdk_config.h

CMSIS Configuration Wizard is integrated with example makefiles. In order to open sdk_config.h in this tool, type:

make sdk_config

Build and Flash

cd blinky/pca10056/mbr/armgcc

# To just build. Optional `-jN` flag, where N is number of cores to use
make

# To build and flash
make flash

# If a SoftDevice is included in your project
make flash_softdevice

Build tasks can also be added to .vscode/tasks.json. Pressing CTRL+SHIFT+B will execute the default build task (in this case, the default build task is make flash for PCA10056).

Segger RTT Log

To use the RTT Viewer equivalent on GNU/Linux, start by opening a terminal and starting JLinkExe.

Follow the steps below to connect the device (in this case, NRF52840_XXAA). Press ENTER to accept the default value. The only option that needs to be changed (aside from board, if necessary) is the target interface (use SWD instead of JTAG).

J-Link>connect
Device>
Please specify target interface:
  J) JTAG (Default)
  S) SWD
  T) cJTAG
TIF>S
Specify target interface speed [kHz]. <Default>: 4000 kHz
Speed>
Device "NRF52840_XXAA" selected.

Alternatively, you can specify the configurations in the command line:

JLinkExe -device NRF52832_XXAA -if SWD -speed 4000 -autoconnect 1

In another terminal, start JLinkRTTClient. RTT output should now start displaying. Output should be as follows:

###RTT Client: ************************************************************ 
###RTT Client: *               SEGGER Microcontroller GmbH                * 
###RTT Client: *   Solutions for real time microcontroller applications   * 
###RTT Client: ************************************************************ 
###RTT Client: *                                                          * 
###RTT Client: *       (c) 2012 - 2016  SEGGER Microcontroller GmbH       * 
###RTT Client: *                                                          * 
###RTT Client: *     www.segger.com     Support: [email protected]       * 
###RTT Client: *                                                          * 
###RTT Client: ************************************************************ 
###RTT Client: *                                                          * 
###RTT Client: * SEGGER J-Link RTT Client   Compiled Apr 12 2019 17:30:19 * 
###RTT Client: *                                                          * 
###RTT Client: ************************************************************ 

###RTT Client: -----------------------------------------------
###RTT Client: Connecting to J-Link RTT Server via localhost:19021  Connected.
SEGGER J-Link V6.44f - Real time terminal output
J-Link OB-SAM3U128-V2-NordicSemi compiled Jan  7 2019 14:07:15 V1.0, SN=683903307
Process: JLinkExe
<info> app: SPI example started.
<info> app: Transfer completed.
<info> app: Transfer completed.
<info> app: Transfer completed.
...

Debugging

Visual Studio Code

1. Open the debug pane (CTRL+SHIFT+D) and select Cortex-Debug.
2. To create a new configuration, select Add Configuration and choose Cortex-Debug.
3. If required, update the executable and/or armToolchainPath in .vscode/launch.json.
4. Hit F5 to start debugging.

Segger O-zone

Using Segger Ozone provides rich insights on memory, assembly instructions, peripheral registers, etc.

Screencap of using Segger Ozone debugger.

New project settings:

1. Select Create new project
2. Choose target device
   • Select device: nRF52840_xxAA (or other)
   • Peripherals: (blank)
3. Connection settings
   • Target interface: SWD
   • Target interface speed: 1 MHz
   • Host interface: USB
   • Serial no: (blank)
4. Program file
   • Select pca10056/mbr/armgcc/_build/nrf52840_xxaa.out

Resources

• Nordic Information Center - Official Documentation