RPi4 CMake project

Development

Your first connection (to the Pi)

To do anything with the Pi you'll need a way to execute commands on it.
You can either hook up a bunch of peripherals and use it like a normal computer.
Or you can SSH into the Pi over Ethernet (I'm going to show you how)

First connect your laptop's Ethernet port directly to the one on your Pi.
(Don't forget to give power to your Pi using a USB-C cable)

Open a terminal on your host PC (laptop) and connect over ssh using:

# "pi" is the default user, and "raspberrypi" is the default hostname.
$ ssh pi@raspberrypi

And boom, you now have a way to execute commands on your Pi.

WiFi on the Pi (from CLI)

Most reliable way to get WiFi on the Pi is by using your Laptop as a WiFi hotspot.
You can enable your hotspot by typing Mobile hotspot into the windows search bar.
Make sure! you have the Band set to 2.4Ghz, otherwise it won't connect.

To setup wifi autoconnect for your hotspot on the Pi you can use the following instructions:

Run sudo raspi-config on your Pi to open the system config.
Navigate to 1 System Options and then S1 Wireless LAN.
At last simply enter your wifi hotspot name, and password. Now the Pi will automatically connect the your hotspot when it's available.

Cross-compilation

^(optional)

Installing (older) Arm cross-compiler

The reason we need an older compiler is because the RPi doesn't support newer versions of GLIBC.
This is why we have to downgrade our version, to avoid a GLIBC required version that is too high.

First, make a bin directory under your user (or wherever you want :p)

$ cd ${HOME}
$ mkdir bin
$ cd bin

Now, that we have somewhere to put our new compiler, let's download the tar ball.
The available binaries can be found at releases.linaro.org.
Pick the version you want (I recommend 6.5 because it worked for my RPi4B)

Next, choose which compiler you want:

ARM 32-bit : arm-linux-gnueabihf
ARM 64-bit : aarch64-linux-gnu

Once inside the folder of the compiler which you need, copy the link to the x86_64**.tar.xz file.
Now at last we can download the compiler binaries using wget.
(replace <link> with the link you copied)

# IMPORTANT: make sure you're still inside your `${HOME}/bin/` directory you created.
$ wget <link>

# EXAMPLE link: https://releases.linaro.org/components/toolchain/binaries/6.5-2018.12/arm-linux-gnueabihf/gcc-linaro-6.5.0-2018.12-x86_64_arm-linux-gnueabihf.tar.xz

Now simply unpack the tar ball using the following command:
(replace <tarball> with the name of the tar ball you downloaded)

$ tar -xf <tarball>

(you can delete the tar ball after unpacking :p)

Finally we've come to the last part of the process, updating your PATH env variable.
First find the bin directory inside the tar ball you just unpacked.
Then run pwd to get the absolute directory to this bin folder.

After obtaining the directory where your new compiler binaries are stored.
Open the ~/.profile file using your favorite text editor.

$ sudo nano ~/.profile

Now look for this part of the file:

# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
    PATH="$HOME/bin:$PATH"
fi

And add your compiler directory in there like so:
(make sure to replace the path with I added as example with yours)

# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
    PATH="$HOME/bin:$PATH"
    # add ARM cross compiler path
    PATH="$HOME/bin/gcc-linaro-6.5.0-2018.12-x86_64_arm-linux-gnueabihf/bin:$PATH"
fi