mruby on bare-metal Raspberry Pi

This is a sample project to use mruby on bare-metal (without OSs such as Linux) Raspberry Pi.

Cf. http://www.slideshare.net/yamanekko/rubyconf2013

Tools

To build and use this sample, you need some tools:

• GNU toolchain for ARM
• Eclipse CDT (optional)
• PC (we use OS X, but you may use it on Linux and Windows)
• armjtag (https://github.com/dwelch67/raspberrypi/tree/master/armjtag) when you want to use JTAG debugger

How to Build

creating mruby project

• menu "Window" -> "Open Perspective" -> "Other..." -> "Git Repository Exploring" and press OK button
• In "Git Repositories" view, press "Clone a Git Repository and add the clone to this view" button
• In "Source Git Repository" Dialog, input "https://github.com/yamanekko/mruby.git" as URL, press Next button
• In "Branch Selection", check "master" and "rubyconf", and press Next button
• In "Local Destination", input (non-existing) directory name as "Directory", "rubyconf" as "Initial branch", and press Finish button
• menu "Window" -> "Open Perspective" -> "Other..." -> "C/C++"
• menu "File" -> "New" -> "Makefile Project with Existing Code"
• In "Import Existing Code", input project name as "Project Name", choose the directory as "Exising Code Loation", check C and C++ as "Languages", choose "Cross GCC" as "Toolchain for Indexer Settings", and press Finish button

Build mruby

• open "build_config.rb" file
• modify the line cc.command='/opt/gnuarm/bin/arm-none-eabi-gcc' in build_config.rb. (If you use arm-none-eabi-gcc in MacPorts, use cc.command='/opt/local/bin/arm-none-eabi-gcc'.)
• modify the line archiver.command='/opt/gnuarm/bin/arm-none-eabi-ar' in build_config.rb. (If MacPorts, use archiver.command='/opt/local/bin/arm-none-eabi-ar'.)
• remove line "MRuby::CrossBuild.new('STM32F4') do" and following lines.
• save build_config.rb ("File" -> "Save")
• "Project" -> "Build Project"

create raspberrypi project

• menu "File" -> "Import..."
• In "Select" dialog, "Git" -> "Project from Git" and press Next button
• In "Select Repository Source" dialog, "Clone URL" and press Next button
• In "Source Git Repository" dialog, input https://github.com/yamanekko/raspberrypi.git as URL and press Next button
• In "Branch Selection" dialog, check "master" and press Next button
• In "Local Destination" dialog, input directory name as "Directory", choose "master" as "Initial branch" and press Next button
• In "Select a wizard to use for importing projects" dialog, choose "Use the New project wizard Import as general projects" as "Wizard for project import" and press Next button
• In "Select a wizard" dialog, choose "Make Project with Existing Code" in "C/C++" and press Next button
• In "Import Existing Code" dialog, input project name as "Project Name", input directory name created earlier as "Exising Code Loation", check "C" and "C++" as "Languages", choose "Cross GCC" as "Toolchain for Indexer Settings" and press Finish button

Build RaspberryPi repository

• open Makefile
• set "ARMGNU" and "LIB" (If MacPorts, use ARMGNU = /opt/local/bin/arm-none-eabi and LIB = -L /opt/local/arm-none-eabi/lib/fpu/ -L/opt/local/lib/gcc/arm-none-eabi/4.7.2/fpu/)
• set "INCDIR" and "ULIBDIR" (If mruby project and raspberrypi project are in the same directory, use INCDIR = ../<mruby project dir>/include/ and ULIBDIR = ../<mruby project dir>/build/rs/lib)
• save Makefile ("File" -> "Save")
• Build the project ("Projec" -> "Build Project")

Execute on Raspberry Pi

• copy kernel.img to SD card
• insert SD card into Raspberry Pi
• power on

Execute on Raspberry Pi with JTAG debugger

(TBD)