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General-Purpose Input/Output Setup for Qt 6 Cross-Compilation

Important

  • Change the hostname and username of Raspberry Pi OS (pi@192.168.30.77)
  • Change the username of Ubuntu (quang)
  • Only one line to copy for each step.
  • One terminal on the host to set up.
  • Plz be patient and calm.

On Raspberry Pi

1. Download wiringPi

cd ~
git clone https://github.com/WiringPi/WiringPi.git

2. Build wiringPi

./build debian
mv debian-template/wiringpi-3.x.deb .
sudo apt install ./wiringpi-3.x.deb

3. Check if wiringPi is installed correctly

  • Check version of gpio

    gpio -v

  • Check in /usr/lib

    ls -l /usr/lib

    Check available file libwiringPiDev.so and libwiringPi.so

  • Check in /usr/include

    ls -l /usr/include

    Check available file wiringPi.h

On host (Ubuntu)

1. rsync

rsync -avz --rsync-path="sudo rsync" pi@192.168.30.77:/usr/include rpi-sysroot/usr
rsync -avz --rsync-path="sudo rsync" pi@192.168.30.77:/usr/lib rpi-sysroot/usr

2. Edit CMakeLists.txt

Create new Qt Widgets Application project in Qt creator then edit file CMakeLists.txt

Important

  • Each new project
    • Under Run section, on X11 Forwarding check Forward to local display and input :0 to the text field.
    • Under Environment section, click Details to expand the environment option. Click Add, then on Variable column type LD_LIBRARY_PATH. On the Value column, type :/usr/local/qt6/lib/. 
      LD_LIBRARY_PATH

      :/usr/local/qt6/lib
  • Delete line: target_link_libraries(showImg PRIVATE Qt${QT_VERSION_MAJOR}::Widgets)
  • Append this code: 
    # --------------------------------------------------------------------------------
#              			 --- Wiring Pi library set up ---
find_library(WIRINGPI_LIB wiringPi PATHS /usr/lib)

if(WIRINGPI_LIB)
    target_link_libraries(gpioTest PRIVATE Qt${QT_VERSION_MAJOR}::Widgets ${WIRINGPI_LIB})
else()
    message(FATAL_ERROR "Không tìm thấy thư viện wiringPi")
endif()
# --------------------------------------------------------------------------------

Note

gpioTest is the name of the project. If you have a different name, you should edit it accordingly.

3. ERORR: Could not find the WiringPi library

rsync -avz --rsync-path="sudo rsync" pi@192.168.30.77:/usr/local/lib rpi-sysroot/usr/local 
ln -sf ~/rpi-sysroot/usr/local/lib/libwiringPi.so.* libwiringPi.so
ln -sf ~/rpi-sysroot/usr/local/lib/libwiringPiDev.so.* libwiringPiDev.so