Thanks for the response, The problem appears below llvm.h in the error report, but if it is clicked then gcc.h is brought up and it says that the parameter CONFIG_ARM isn't defined, and the cortex-M33 is an ARM board, so it should be(?). We don't really even know where it should be defined.
I'm trying to do some test with SPI with the nRF5340-DK, so I made a new project, and I can build that just fine, but if I add the line to include the header file for the SPI (drivers/SPI.h) then I get an error: "processor architecture not supported" I'm using gcc as a compiler, if that makes a difference. In the project options menu, the ARM Architecture is listed as "v8M", and the ARM Core Type is "Cortex-M33" An image of the build report is attached. I'm not all that experienced with this pro…