Installation of lightweight LinuxCNC HAL in Raspberry Pi 4 + EtherCAT

💾 Preparing the MicroSD image:

Download the pre-compiled image from LinuxCNC project website:

http://www.linuxcnc.org/iso/linuxcnc-2.8.1-pi4.zip

Connect the microSD card in the computer and see the device name with:

lsblk -l

Now attach the microSD card in the computer:

You should see sometihng like /dev/sda

Uncompress the zip file and write the image into the microSD card:

sudo dd if=2021-01-20-linuxcnc-pi4.img of=/dev/[your device]

🙌🏿 In case you want to do all the instalation headless (Wifi + SSH). Do the following steps in the microSD boot partition:

📶 Enable SSH server in our Raspberry Pi.

touch ssh

📡 Configure the Wifi access:

Creating a wpa_supplicant.conf file.

touch wpa_supplicant.conf

Adding configuration to our file (Copy paste it, and change the Wifi SSID and PASSWORD) :

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=FI

network={
ssid="SSID"
psk="PASSWORD"
}

• Change SSID (your wifi name) and PASSWORD (wifi password) inside the double quotation marks

📥 Start HAL-Core installation:

Once we connect that to the power and we have internet access:

First we update repositories, them we upgrade the softwares and after that we reboot the system:

sudo apt update -y

If you get this, press 'y' and them the enter key:

E: Repository 'http://raspbian.raspberrypi.org/raspbian buster InRelease' changed its 'Suite' value from 'stable' to 'oldstable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N] y

then continue:

sudo apt upgrade -y
sudo reboot

If we get some prompt asking, just press y and enter key.

Installing the realtime kernel header:

sudo apt install linux-headers-4.19.71-rt24-v7l -y

Installing development tools needed to install Etherlabmaster:

sudo apt install mercurial build-essential automake tree dkms bison flex -y

Installing Etherlabmaster:

git clone https://github.com/icshwi/etherlabmaster
cd etherlabmaster
make init
echo "ENABLE_CYCLES = NO" > configure/CONFIG_OPTIONS.local
make build
make install
echo "ETHERCAT_MASTER0=eth0" > ethercatmaster.local
make dkms_add
make dkms_build
make dkms_install
make setup

Because the files and libraries are in /opt/etherlab/ we linked it to /usr/lib/ and reboot.

sudo ln -s /opt/etherlab/lib/lib* /usr/lib/
sudo reboot

At this point we have the EtherCAT master working and running everytime the system starts.

Have a try with the following command:

ethercat master

Installing packages needed for HAL:

sudo apt install libmodbus-dev libusb-1.0 libglib2.0-dev yapps2 libreadline-gplv2-dev tcl8.6-dev tclx8.4 tk8.6-dev libboost-python-dev

Downloading HAL (Hardware Abstraction Layer):

Because we place HAl in /opt/ we need to change the user access to it and not use always root permisions.

sudo git clone https://github.com/jjrbfi/lcnc_hal-core_ros.git /opt/hal-core
sudo chown -R pi:pi /opt/hal-core/
/opt/hal-core/./make

Remove halcmd that already comes with the Rpi 4 image and link our new:

sudo rm /usr/bin/halcmd
sudo ln -s bin/halcmd /usr/bin/halcmd

To full STOP halcmd:

If you use the same image provide here Due right now in hal-core do not have halrun, if we want to clean the hal enviroment we need to run the following:

/opt/hal-core/bin/./halcmd stop
kill `pgrep rtapi_app`
kill `pgrep lcec_conf`

At this point we have everything needed to launch our EtherCAT master + HAL ...

Source: https://forum.linuxcnc.org