diff --git a/hw/bsp/family_support.cmake b/hw/bsp/family_support.cmake
index af0e00b2..a8cc1f36 100644
--- a/hw/bsp/family_support.cmake
+++ b/hw/bsp/family_support.cmake
@@ -11,23 +11,52 @@ if (NOT TARGET _family_support_marker)
 
     function(family_filter RESULT DIR)
         get_filename_component(DIR ${DIR} ABSOLUTE BASE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
-        file(GLOB ONLYS "${DIR}/.only.MCU_*")
-        if (ONLYS)
+
+        if (EXISTS "${DIR}/only.txt")
+            file(READ "${DIR}/only.txt" ONLYS)
+            # Replace newlines with semicolon so that it is treated as a list by CMake
+            string(REPLACE "\n" ";" ONLYS_LINES ${ONLYS})
+            # For each mcu
             foreach(MCU IN LISTS FAMILY_MCUS)
-                if (EXISTS ${DIR}/.only.MCU_${MCU})
-                    set(${RESULT} 1 PARENT_SCOPE)
-                    return()
-                endif()
+                # For each line in only.txt
+                foreach(_line ${ONLYS_LINES})
+                    # If mcu:xxx exists for this mcu then include
+                    if (${_line} STREQUAL "mcu:${MCU}")
+                        set(${RESULT} 1 PARENT_SCOPE)
+                        return()
+                    endif()
+                endforeach()
             endforeach()
+
+            # Didn't find it in only file so don't build
+            set(${RESULT} 0 PARENT_SCOPE)
+
+        elseif (EXISTS "${DIR}/skip.txt")
+            file(READ "${DIR}/skip.txt" SKIPS)
+            # Replace newlines with semicolon so that it is treated as a list by CMake
+            string(REPLACE "\n" ";" SKIPS_LINES ${SKIPS})
+            # For each mcu
+            foreach(MCU IN LISTS FAMILY_MCUS)
+                # For each line in only.txt
+                foreach(_line ${SKIPS_LINES})
+                    # If mcu:xxx exists for this mcu then skip
+                    if (${_line} STREQUAL "mcu:${MCU}")
+                        set(${RESULT} 0 PARENT_SCOPE)
+                        return()
+                    endif()
+                endforeach()
+            endforeach()
+
+            # Didn't find in skip file so build
+            set(${RESULT} 1 PARENT_SCOPE)
+
         else()
-            foreach(MCU IN LISTS FAMILY_MCUS)
-                if (EXISTS ${DIR}/.skip.MCU_${MCU})
-                    set(${RESULT} 0 PARENT_SCOPE)
-                    return()
-                endif()
-            endforeach()
+
+            # Didn't find skip or only file so build
+            set(${RESULT} 1 PARENT_SCOPE)
+
         endif()
-        set(${RESULT} 1 PARENT_SCOPE)
+
     endfunction()
 
     function(family_add_subdirectory DIR)