Software development

Shared files

The firmware is highly configurable and highly portable. To achieve that, it is split in multiple parts:

• The core source files, which are common to every target, especially the Virtual Machine
• the ports, dedicated to an embedded MCU and board
• The tests, to easily test part of source on a standard PC
• A desktop/mobile implementation

The core is written in pure C, targets implementations may add other languages and libraries (QML/C++/python ...).

Software projects

• The Story Editor project is located in story-editor directory, it is programmed in C++ and uses the Qt library
• The multi-platform software player is located in story-player, it is programmed in C and uses the Raylib library

Firmware project

Only one CMakeLists.txt project file is used to build all the official bundles.

Firmware build system

The project uses CMake as build system. For the embedded targets, the main CMakeLists.txt includes a generic cross compiler file that should be good for many configurations as soon as your compiler is GCC.

The CMake file is located in software directory.

Command line invocation

1. Create a build directory (mkdir build)
2. Invoke cmake with some options, passed as definitions for CMake (-Doption)

Option	Role
TOOLCHAIN	specify the prefix name of the cross GCC binary
CMAKE_TOOLCHAIN_FILE	Includes before everything else a compiler toolchain file
CMAKE_BUILD_TYPE	Debug or Release (default ?)
OST_BUNDLE	Specify the bundle name to build
TOOLCHAIN_DIR	Specify a directory for the cross-gcc toolchain location

Example: cmake -DTOOLCHAIN=riscv64-unknown-elf -DCMAKE_TOOLCHAIN_FILE=cmake/cross-gcc.cmake -DCMAKE_BUILD_TYPE=Debug -DOST_BUNDLE=LONGAN_NANO ..

The most important option is OST_BUNDLE which defines the hardware target.

IDE Developement

You can use any C++ editor you want but we provide a ready to use and debug configuration for Visual Studio Code.

Recommanded plugins are:

• Microsoft C/C++ Extension Pack
• Microsoft CMake tools
• Cortex-Debug

With VSCode, open the directory software as root of your tree view.

1. We provide a ready to use JTAG probe configurations in the launch.json file
2. Debug with the tool at the top
3. Build shortcut!
4. CMakeLists.txt must be located at the root of your tree view.

Debugging

To debug embedded targets, we usually connect a hardware probe between the computer and the processor. We suggest to use the following probes which are supported by our scripts:

• Segger JLink (great performance) for ARM and RISC-V cores
• Black-Magic Probe (embeds a GDB server, native debugging with GDB)