set(BOARD_REVISIONS "minima" "wifi") if(NOT DEFINED BOARD_REVISION) set(BOARD_REVISION "minima") else() if(NOT BOARD_REVISION IN_LIST BOARD_REVISIONS) message(FATAL_ERROR "${BOARD_REVISION} is not a valid revision for arduino_uno_r4. Accepted revisions: ${BOARD_REVISIONS}") endif() endif()