Hi there,
For sake of argument, just letting you all know that I tried to test support for CODESYS 3.5.13.0 under Diet Pi v6.12 and
I can confirm that the SPI interface is working fine in combination with CODESYS
See https://store.codesys.com/codesys-control-for-raspberry-pi-sl.html?___store=en for details of the software.
Offcourse, Codesys will not officially test/support this OS and your mileage may vary.
But since DietPi is based of Raspbian, the Runtime should work as expected as it is developed for vanilla Raspbian.
Small walkthrough;
I installed latest DietPi Image on an SD Card, adjusted the network and WIFI settings.
Then booted into the pi and ran DietPi-Config to enable i2c support. Also I edited raspi-config.txt in the boot directory to enable the SPI interface.
Now, getting the CODESYS runtime installed should be done manually by copying the .deb file to the SD Card.
Then, boot into the OS and via ssh and type;
sudo dpkg -i /boot/codesyscontrol_arm_raspberry_V3.5.13.0.deb
Viola, your raspberry diet-pi based PLC is ready for usage!
Great for โprefessionalโ IoT projects!
Enjoy