Raspberry Pi: turn on, off, blink the Green ACT LED

Environment
  • Ubuntu 16.04 LTS
  • Raspberry Pi 3 Model B
Turn on, off, blink the Green ACT LED
# We need root permissions
$ sudo -i
# Turn On
$ echo none > /sys/class/leds/led0/trigger
$ echo 1 > /sys/class/leds/led0/brightness
# Turn Off, echo none to trigger is not required
$ echo 0 > /sys/class/leds/led0/brightness
# Blink
$ echo timer > /sys/class/leds/led0/trigger

 

Raspberry Pi: key-based authentication

Environment
  • Ubuntu 16.04 LTS
  • Raspberry Pi 3 Model B

Key-based authentication is a nice alternative to username/password-based login. Below is a basic process describing how to generate an RSA key pair and install public key on Raspberry Pi.

For more info see How to configure ssh key-based authentication on a linux server.

Create RSA key pair
$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user/.ssh/id_rsa):        
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/user/.ssh/id_rsa.
Your public key has been saved in /home/user/.ssh/id_rsa.pub.
The key fingerprint is:
...

The key will be created in the ~/.ssh folder by default.

Upload public key to Raspberry Pi
$ cat ~/.ssh/id_rsa.pub | ssh pi@192.168.0.xxx "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"

Alternatively, use ssh-copy-id:

$ ssh-copy-id pi@192.168.0.xxx
Key-based authentication

Start ssh session as usually, password will not be required:

$ ssh pi@192.168.0.xxx

Raspberry Pi: gdb debugging in Eclipse

If you want to do gdb debugging on command line – see Raspberry Pi: gdb debugging, command line.

In case you are interested how to debug Dart command line applications in IntelliJ – see Raspberry Pi: How to remote debug Dart command line applications in IntelliJ.

Environment
  • Ubuntu 16.04 LTS
  • Eclipse Neon.3 Release 4.6.3
  • arm-linux-gnueabihf (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
  • Raspberry Pi 3 Model B

Based on this and this GuruCoding pages.

ARM toolchain

See Raspberry Pi: cross-compiling blog.

Install Eclipse IDE for C/C++ developers

Download and install from here.

Create and compile an example project

See Raspberry Pi: cross-compiling in Eclipse blog.

Set up remote access in Eclipse
  • Window > Perspective > Open perspective > Other > Remote System Explorer
  • File > New > Other > Remote System Explorer > Connection
  • Select Remote System Type:
    • Linux
    • Next
  • Remote System Connection:
    • Host name: raspberry-pi
    • Connection name: raspberry-pi
    • Next
  • Files:
    • Configuration: ssh.files
    • Next
  • Processes
    • Configuration: processes-shell-linux
    • Next
  • Shells:
    • Configuration: ssh-shells
    • Next
  • Ssh Terminals:
    • Configuration: ssh.terminals
    • Finish
  • Right click created connection > Properties
    • Host > Default User Id: pi
Create project

In Eclipse:

  • File > New > C++ Project
  • C++ Project
    • Project name: helloworld
    • Project type: Hello World C++ Project
    • Toolchains: Cross GCC
    • Next
  • Basic Settings
    • Hello world greeting: Hello world!
    • Next
  • Select Configurations
    • Next
  • Cross GCC Command
    • Cross compiler prefix: arm-linux-gnueabihf-
    • Cross compiler path: /usr/sbin
    • Finish
  • Right-click project name > Properties > C/C++ Settings
    • Tool Settings > Cross Settings
      • Prefix: arm-linux-gnueabihf-
      • Path: /usr/sbin
  • Project > Build All

Raspberry Pi: how to solve the “version `GLIBCXX_6.0.21′ not found” problem

Environment
  • Ubuntu 16.04 LTS
  • arm-linux-gnueabihf (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
  • Raspberry Pi 3 Model B
Upgrade libstdc++ to 6.0.21

If you use arm-linux-gnueabihf toolchain (see Raspberry Pi: C++ cross-compiling) to build your applications for Raspberry Pi then there is a chance that you’ll have to upgrade your Raspbbery Pi libstdc++ to the toolchain’s version 6.0.21 (or later).

Ubuntu:

$ scp /usr/arm-linux-gnueabihf/lib/libstdc++.so.6.0.21 pi@192.168.0.xxx:/home/pi

Raspberry Pi:

$ sudo mv libstdc++.so.6.0.21 /usr/lib/arm-linux-gnueabihf/
$ sudo ln -s /usr/lib/arm-linux-gnueabihf/libstdc++.so.6.0.21 /usr/lib/arm-linux-gnueabihf/libstdc++.so.6

Raspberry Pi: install Dart VM, create and run helloword.dart

Environment
  • Ubuntu 16.04 LTS
  • arm-linux-gnueabihf (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
  • Dart SDK, master 1.24.0-edge.eb1839b8fd453b6c0c93376346743fa96db48440
  • Raspberry Pi 3 Model B
Download and build Dart SDK

See Dart: build Dart SDK for x86 and ARM.

Important: though Raspberry Pi 3 has a 64-bit CPU the Raspbian OS does not support 64-bit builds at the moment of writing – we will build 32-bit Dart SDK for ARM.

Alternatively, you can download pre-built Dart SDK for ARM:

$ wget https://storage.googleapis.com/dart-archive/channels/stable/release/1.22.1/sdk/dartsdk-linux-arm-release.zip
Upgrade libstdc++ to 6.0.21

See Raspberry Pi: how to solve the “version `GLIBCXX_6.0.21′ not found” problem.

Copy Dart VM to Raspbbery Pi

Ubuntu:

$ cd dart-sdk/sdk
$ scp -r out/ReleaseXARM/dart-sdk/bin/dart pi@192.168.0.xxx:/home/pi

Raspberry Pi:

$ sudo mv dart /usr/local/bin

Restart Raspberry Pi ssh session, then check if Dart VM works:

$ dart --version
Dart VM version: 1.24.0-edge.eb1839b8fd453b6c0c93376346743fa96db48440 (Sun Apr 16 18:04:59 2017) on "linux_arm"
Hello World application

Create helloworld.dart file with the following content:

main() {
  print('Hello world!');
}

Run the application:

$ dart helloworld.dart 
Hello world!

 

 

 

Dart: build Dart SDK for x86 and ARM

Based on Building Dart, Building Dart SDK for ARM processors and Building Dart SDK for Raspberry Pi.

Environment
  • Ubuntu 16.04 LTS
  • arm-linux-gnueabihf (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
  • Dart SDK, master f6a2fb0050eeaf24706da66bdd73c2f3c9770f96
x86 toolchain

Pre-installed in Ubuntu (16.04 LTS).

ARM 32-bit toolchain

See Raspberry Pi: C++ cross-compiling .

ARM 64-bit toolchain
$ sudo apt-get install g++-aarch64-linux-gnu
Other build tools
$ sudo apt-get install g++ git make python
$ sudo apt-get install g++-multilib
Install Chromium depot_toops
$ git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
$ export PATH="$PATH:$PWD/depot_tools"
Get the source
$ mkdir dart-sdk
$ cd dart-sdk
$ gclient config https://github.com/dart-lang/sdk.git
### Checkout HEAD
$ gclient sync
### Checkout a tag, e.g. 1.9.3
$ gclient sync --revision=1.9.3
Create (if missing) symbolic links

create_sdk build will fail if the following symbolic links are missing:

$ sudo ln -s /usr/include/x86_64-linux-gnu/asm/ /usr/include/asm
$ sudo ln -s /usr/include/x86_64-linux-gnu/bits/ /usr/include/bits
Build 64-bit x86
$ cd dart-sdk/sdk
$ ./tools/build.py --mode release --arch x64 create_sdk
Build 32-bit x86
$ cd dart-sdk/sdk
$ ./tools/build.py --mode release --arch ia32 create_sdk
Build for 32-bit ARM
$ cd dart-sdk/sdk
$ ./tools/build.py --mode release --arch arm create_sdk

The build fails (master #eb1839b):

g++ -MMD -MF x86/obj/runtime/bin/gen_snapshot_dart_io/eventhandler_linux.o.d -DDART_IO_SECURE_SOCKET_DISABLED -D_FORTIFY_SOURCE=2 -DNDEBUG -DTARGET_OS_LINUX -DTARGET_ARCH_ARM -DNDEBUG -DDART_USE_TCMALLOC -DDART_PRECOMPILER -I../../runtime -I../../third_party -I../.. -Ix86/gen -I../../third_party/tcmalloc/gperftools/src -I../../third_party/zlib -m32 -msse2 -mfpmath=sse -fno-exceptions -pthread -Wall -Wextra -Werror -Wendif-labels -Wno-missing-field-initializers -Wno-unused-parameter -Wno-unused-local-typedefs -O3 -fno-ident -fdata-sections -ffunction-sections -g3 -ggdb3 -Werror -Wall -Wextra -Wno-unused-parameter -Wnon-virtual-dtor -Wvla -Wno-conversion-null -Woverloaded-virtual -g3 -ggdb3 -fno-rtti -fno-exceptions -O3 -fvisibility-inlines-hidden -fno-omit-frame-pointer -fno-rtti -fno-exceptions -c ../../runtime/bin/eventhandler_linux.cc -o x86/obj/runtime/bin/gen_snapshot_dart_io/eventhandler_linux.o
In file included from ../../runtime/vm/simulator_arm.h:19:0,
                 from ../../runtime/vm/simulator.h:15,
                 from ../../runtime/vm/atomic.h:11,
                 from ../../runtime/bin/reference_counting.h:8,
                 from ../../runtime/bin/socket.h:14,
                 from ../../runtime/bin/eventhandler_linux.cc:27:
../../runtime/vm/constants_arm.h:263:17: error: ‘dart::STMP’ defined but not used [-Werror=unused-variable]
 const SRegister STMP = EvenSRegisterOf(DTMP);
                 ^
cc1plus: all warnings being treated as errors
ninja: build stopped: subcommand failed.
BUILD FAILED

This can be fixed by changing the dart-sdk/sdk/runtime/vm/constants_arm.h file, lines 262-263 from:

const DRegister DTMP = EvenDRegisterOf(QTMP);  
const SRegister STMP = EvenSRegisterOf(DTMP);

to:

const DRegister DTMP __attribute__((unused)) = EvenDRegisterOf(QTMP);  
const SRegister STMP __attribute__((unused)) = EvenSRegisterOf(DTMP);

Raspberry Pi note: This procedure will produce a useful Dart VM – the dart and pub utilities.

Pre-built 32-bit ARM Dart SDK image
$ wget http://share.geomodule.com/dart-sdk-f6a2fb0050eeaf24706da66bdd73c2f3c9770f96.tar.gz
Build for 64-bit ARM
$ cd dart-sdk/sdk
./tools/build.py --mode release --arch arm64 create_sd
Install Dart SDK on Raspberry Pi

Make sure you have correct version of the GLIBCXX library, see here:

http://sw-eng-notes.geomodule.com/2017/04/16/raspberry-pi-how-to-solve-version-glibcxx_6-0-21-not-found/

# On your build host host
$ cd dart-sdk
$ scp -r sdk/out/ReleaseXARM/dart-sdk pi@192.168.0.xxx:~/dart-sdk
# On Raspberry Pi
# Add the following line at the end of .bashrc
# export PATH=${PATH}:/home/pi/dart-sdk/bin
$ dart --version
Dart VM version: 1.24.0-edge.eb1839b8fd453b6c0c93376346743fa96db48440 (Sun Apr 16 18:04:59 2017) on "linux_arm"
$ pub --version
Pub 1.25.0-edge.511963d71509de50ac577ac22f3bac8d33c17e34

Raspberry Pi: C++ cross-compiling in Eclipse

Based on this GuruCoding page.

Environment
  • Ubuntu 16.04 LTS
  • Eclipse Neon.3 Release 4.6.3
  • arm-linux-gnueabihf (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
  • Raspberry Pi 3 Model B
ARM toolchain

See Raspberry Pi: cross-compiling blog.

Upgrade libstdc++ to 6.0.21 on Raspberry Pi

See Raspberry Pi: how to solve the “version `GLIBCXX_6.0.21′ not found” problem.

Install Eclipse IDE for C/C++ developers

Download, unpack from here.

Eclipse plugins

Eclipse:

  • Help > Install new software > Work with: –All Available Sites–
  • Check “Mobile and Device Development”
  • Next > Accept the terms of the license agreement” > Finish
  • Restart Eclipse
Create project

In Eclipse:

  • File > New > C++ Project
  • C++ Project
    • Project name: helloworld
    • Project type: Hello World C++ Project
    • Toolchains: Cross GCC
    • Next
  • Basic Settings
    • Hello world greeting: Hello world!
    • Next
  • Select Configurations
    • Next
  • Cross GCC Command
    • Cross compiler prefix: arm-linux-gnueabihf-
    • Cross compiler path: /usr/bin
    • Finish
  • Project > Properties > C/C++ Build > Settings
    • Tool Settings > Cross Settings
      • Prefix: arm-linux-gnueabihf-
      • Path: /usr/bin
Enable C++ 11
  • Project > Properties > C/C++ Build > Settings
    • Configuration: Debug/Release
    • Tool Settings > Cross G++ Compiler > Dialect: ISO C+11 (-std=c++0x)
Build
  • Project > Build All

Raspberry Pi: debugging with gdb, command line

20170325

This post is about how to debug Raspberry Pi software with gdb, command line. For gdb debugging in Eclipse see Raspberry Pi: gdb debugging in Eclipse.

In case you are interested how to debug Dart command line applications in IntelliJ – see Raspberry Pi: How to remote debug Dart command line applications in IntelliJ.

Environment

  • Ubuntu 16.04 LTS
  • arm-linux-gnueabihf (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
  • Raspberry Pi 3 Model B

Prepare/compile helloworld

See here.

Install gdb-multiarch on host

$ sudo apt-get install gdb-multiarch

Install gdbserver on Raspberry Pi

$ sudo apt-get install gdbserver

Debug

# On target, 192.168.0.131 - debug host's ip address
$ gdbserver --multi 192.168.0.131:2345
Listening on port 2345

# On host, 192.168.0.140 - target ip address
$ gdb-multiarch
GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
Copyright (C) 2016 Free Software Foundation, Inc.
...
For help, type "help".
Type "apropos word" to search for commands related to "word".
(gdb) target extended-remote 192.168.0.140:2345
Remote debugging using 192.168.0.140:2345
(gdb) set remote exec-file /home/pi/path/helloworld
(gdb) file /home/uname/path/helloworld
Reading symbols from /home/uname/path/helloworld...done.
(gdb) start
Temporary breakpoint 1 at 0x105f4: file src/helloworld.cpp, line 12.
Starting program: /home/uname/path/helloworld 
...
Temporary breakpoint 1, main () at src/helloworld.cpp:12
12    int main() {
(gdb) next
13        std::cout << "Hello World!" << std::endl;
(gdb) next
12    int main() {
(gdb) next
13        std::cout << "Hello World!" << std::endl;
(gdb) next
12    int main() {
(gdb) next
13        std::cout << "Hello World!" << std::endl;
(gdb) next
15    }

# On target
Remote debugging from host 192.168.0.131
Process /home/pi/path/helloworld created; pid = 2267
Hello World!

 

Raspberry Pi: C++ cross-compiling

Environment
  • Ubuntu 16.04 LTS
  • arm-linux-gnueabihf (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
  • Raspberry Pi 3 Model B
Install build tools

Check/install build-essential:

# Check if build-essential is installed
$ dpkg -s build-essntial
# Install build-essential if needed
$ sudo apt-get install build-essential
Install ARM toolchain
# ARM build tools
$ sudo apt-get install g++-arm-linux-gnueabihf
# Check installation
$ arm-linux-gnueabihf-g++ -v
Upgrade libstdc++ to 6.0.21 on Raspberry Pi

See Raspberry Pi: how to solve the “version `GLIBCXX_6.0.21′ not found” problem.

Create helloworld.cpp
#include <iostream>

int main() {
    std::cout << "Hello World!" << std::endl;
    return 0;
}
Compile
$ arm-linux-gnueabihf-g++ -O3 -g3 -Wall -fPIC -c -o helloworld.o helloworld.cpp
$ arm-linux-gnueabihf-g++ -o helloworld helloworld.o
Copy helloworld to Raspberry Pi
$ scp ./helloworld pi@192.168.0.xxx:/home/pi/path
Login into Raspberry Pi and run helloworld
$ ssh pi@192.168.0.xxx
# On Raspberry Pi
$ cd path
$ ./helloworld
Hello World!
g++-arm-linux-gnueabihf pakage detais
$ dpkg -s g++-arm-linux-gnueabihf
Package: g++-arm-linux-gnueabihf
Status: install ok installed
Priority: optional
Section: devel
Installed-Size: 11
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Architecture: amd64
Source: gcc-defaults (1.150ubuntu1)
Version: 4:5.3.1-1ubuntu1
Depends: cpp-arm-linux-gnueabihf (>= 4:5.3.1-1ubuntu1), gcc-arm-linux-gnueabihf (>= 4:5.3.1-1ubuntu1), g++-5-arm-linux-gnueabihf (>= 5.3.1-3~)
Description: GNU C++ compiler for the armhf architecture
 This is the GNU C++ compiler, a fairly portable optimizing compiler for C++.
 .
 This is a dependency package providing the default GNU C++ cross-compiler
 for the armhf architecture.
Original-Maintainer: Debian GCC Maintainers <debian-gcc@lists.debian.org>

Fuchsia OS: download, build and run

20161029

Supported build platforms

At the moment of writing two build platforms seems to be supported – Ubuntu and Mac OSx. This article focuses on Ubuntu.

Getting the source

How to install version control tools and checkout Fuchsia OS repositories is described on the Fuchsia Manifest page:

# Install tools
sudo apt-get install golang git-all build-essential curl
# Install jiri scripts
curl -s https://raw.githubusercontent.com/fuchsia-mirror/jiri/master/scripts/bootstrap_jiri | bash -s fuchsia
# Export path to jiri
cd fuchsia
export PATH=`pwd`/.jiri_root/bin:$PATH
# Import/update Fuchsia code
jiri import fuchsia https://fuchsia.googlesource.com/manifest
jiri update

Building Fuchsia

Build instructions can be found in the Fuchsia Repository:

# Setup build environment, amr64
source scripts/env.sh && envprompt && fset arm64
# Build
fbuild

Built sysroot will be in:

fuchsia/out/sysroot/aarch64-fuchsia

and the boot image in:

fuchsia/out/debug-aarch64/user.bootfs

cc

cd fuchsia
git clone https://fuchsia.googlesource.com/third_party/qemu
cd qemu
./configure --target-list=arm-softmmu,aarch64-softmmu,x86_64-softmmu
make -j32
sudo make install

Run Fuchsia OS in QEMU

cd fuchsia/magenta
# Run aarch64 (optionally, with graphical consol - add -g)
./scripts/run-magenta-arm64 -x ../out/debug-aarch64/user.bootfs -m 2048 [-g]

Magenta on Raspberry PI

See Magenta on Raspberry Pi and Raspberry Pi: compile and run Magenta pages.