diff --git a/global.c b/global.c
index 677ad2f..080c46c 100644
--- a/global.c
+++ b/global.c
@@ -64,21 +64,24 @@ char* b2s(uint64_t binary, uint8_t rjust)
 }
 
 /** switch on board LED */
-void led_on(void)
+inline void led_on(void)
 {
+#if defined(LED_PIN)
 #if defined(BUSVOODOO)
 	gpio_set_mode(GPIO(LED_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(LED_PIN)); // set LED pin push-pull
-#endif
+#endif // BUSVOODOO
 #if defined(LED_ON) && LED_ON
 	gpio_set(GPIO(LED_PORT), GPIO(LED_PIN));
 #else
 	gpio_clear(GPIO(LED_PORT), GPIO(LED_PIN));
-#endif
+#endif // LED_ON
+#endif // LED_PIN
 }
 
 /** switch off board LED */
-void led_off(void)
+inline void led_off(void)
 {
+#if defined(LED_PIN)
 #if defined(BUSVOODOO)
 	gpio_set_mode(GPIO(LED_PORT), GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO(LED_PIN)); // set LED pin to floating to disable LEDs
 #else
@@ -86,17 +89,20 @@ void led_off(void)
 	gpio_clear(GPIO(LED_PORT), GPIO(LED_PIN));
 #else
 	gpio_set(GPIO(LED_PORT), GPIO(LED_PIN));
-#endif
-#endif
+#endif // BUSVOODOO
+#endif // LED_ON
+#endif // LED_PIN
 }
 
 /** toggle board LED */
-void led_toggle(void)
+inline void led_toggle(void)
 {
+#if defined(LED_PIN)
 #if defined(BUSVOODOO)
 	gpio_set_mode(GPIO(LED_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(LED_PIN)); // set LED pin to push-pull
-#endif
+#endif // BUSVOODOO
 	gpio_toggle(GPIO(LED_PORT), GPIO(LED_PIN));
+#endif // LED_PIN
 }
 
 void sleep_us(uint32_t duration)
@@ -178,6 +184,7 @@ void user_input_store(char c)
 
 void board_setup(void)
 {
+#if defined(LED_PIN)
 	// setup LED
 	rcc_periph_clock_enable(RCC_GPIO(LED_PORT)); // enable clock for LED
 #if defined(BUSVOODOO)
@@ -186,6 +193,7 @@ void board_setup(void)
 	gpio_set_mode(GPIO(LED_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(LED_PIN)); // set LED pin to output push-pull do drive LED
 #endif
 	led_off(); // switch off LED per default
+#endif // LED_PIN
 
 	// setup button
 #if defined(BUTTON_PORT) && defined(BUTTON_PIN)