diff --git a/tests/driver_pir/Makefile b/tests/driver_pir/Makefile
index 0187a02d12..d446513c1f 100644
--- a/tests/driver_pir/Makefile
+++ b/tests/driver_pir/Makefile
@@ -3,23 +3,22 @@ include ../Makefile.tests_common
 
 FEATURES_REQUIRED = periph_gpio
 
-# Define default pin mappings for some boards:
-ifneq (,$(filter stm32f4discovery,$(BOARD)))
-  export PIR_GPIO ?= GPIO_PIN\(3,7\)
-endif
-ifneq (,$(filter arduino-due,$(BOARD)))
-  export PIR_GPIO ?= GPIO_PIN\(0,20\)
-endif
-
 USEMODULE += pir
 USEMODULE += xtimer
 
-ifneq (,$(PIR_GPIO))
-  CFLAGS += -DPIR_GPIO=$(PIR_GPIO)
-else
-  # set random default
-  CFLAGS += -DPIR_GPIO=GPIO_PIN\(0,0\)
+# define parameters for selected boards
+ifneq (,$(filter stm32f4discovery,$(BOARD)))
+  PIR_GPIO ?= GPIO_PIN\(3,7\)
 endif
+ifneq (,$(filter arduino-due,$(BOARD)))
+  PIR_GPIO ?= GPIO_PIN\(0,20\)
+endif
+
+# set default device parameters in case they are undefined
+PIR_GPIO ?= GPIO_PIN\(0,0\)
+
+# export parameters
+CFLAGS += -DPIR_GPIO=$(PIR_GPIO)
 
 include $(RIOTBASE)/Makefile.include