Hello Martin,
The processor of the ctrlX CORE is ARM64 architecture. You can see the technical details in the online documentation "ctrlX CORE Controls, Operating Manual --> Technical data --> General technical data".
If you want to build software for the ctrlX CORE, please have a look at the SDK on GitHub. Within the SDK is also a development environment, which you can use to compile code and pack your snaps (software container) for the ctrlX CORE.
Here are some other useful links for you:
How to setup a ctrlX AUTOMATION development environment
SDK - technical documentation
Snapcraft - creating a snap
Some more How To blogs and videos about the SDK and other topics
Best regards,
Nick
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