diff --git a/hardware/arduino/avr/cores/arduino/wiring_digital.c b/hardware/arduino/avr/cores/arduino/wiring_digital.c
index 27a62fc6cde..bf91fff2fc2 100644
--- a/hardware/arduino/avr/cores/arduino/wiring_digital.c
+++ b/hardware/arduino/avr/cores/arduino/wiring_digital.c
@@ -28,12 +28,12 @@
 
 void pinMode(uint8_t pin, uint8_t mode)
 {
+	if (pin >= NUM_DIGITAL_PINS) return;
+
 	uint8_t bit = digitalPinToBitMask(pin);
 	uint8_t port = digitalPinToPort(pin);
 	volatile uint8_t *reg, *out;
 
-	if (port == NOT_A_PIN) return;
-
 	// JWS: can I let the optimizer do this?
 	reg = portModeRegister(port);
 	out = portOutputRegister(port);
@@ -137,13 +137,13 @@ static void turnOffPWM(uint8_t timer)
 
 void digitalWrite(uint8_t pin, uint8_t val)
 {
+	if (pin >= NUM_DIGITAL_PINS) return;
+
 	uint8_t timer = digitalPinToTimer(pin);
 	uint8_t bit = digitalPinToBitMask(pin);
 	uint8_t port = digitalPinToPort(pin);
 	volatile uint8_t *out;
 
-	if (port == NOT_A_PIN) return;
-
 	// If the pin that support PWM output, we need to turn it off
 	// before doing a digital write.
 	if (timer != NOT_ON_TIMER) turnOffPWM(timer);
@@ -164,12 +164,12 @@ void digitalWrite(uint8_t pin, uint8_t val)
 
 int digitalRead(uint8_t pin)
 {
+	if (pin >= NUM_DIGITAL_PINS) return LOW;
+
 	uint8_t timer = digitalPinToTimer(pin);
 	uint8_t bit = digitalPinToBitMask(pin);
 	uint8_t port = digitalPinToPort(pin);
 
-	if (port == NOT_A_PIN) return LOW;
-
 	// If the pin that support PWM output, we need to turn it off
 	// before getting a digital reading.
 	if (timer != NOT_ON_TIMER) turnOffPWM(timer);