diff --git a/hal/at90usb646/gpio.c b/hal/at90usb646/gpio.c
index bf5dee2..dd6d62a 100644
--- a/hal/at90usb646/gpio.c
+++ b/hal/at90usb646/gpio.c
@@ -75,6 +75,18 @@ void GPIO_SetPullup(GPIOPin pin, bool pullup)
 	GPIO_Set(pin, pullup);
 }
 
+/**
+ * @brief Sets whether an input GPIO pin is pulled down
+ * @param pin The pin
+ * @param pulldown True if it should be pulled down, false if not
+ */
+void GPIO_SetPulldown(GPIOPin pin, bool pulldown)
+{
+	(void)pin;
+	(void)pulldown;
+	// The AVR doesn't support pulldowns
+}
+
 /** Turns a GPIO pin on (sets it high)
  *
  * @param pin The pin
diff --git a/hal/gpio.h b/hal/gpio.h
index 660e1c7..5a333a1 100644
--- a/hal/gpio.h
+++ b/hal/gpio.h
@@ -43,6 +43,7 @@ typedef struct GPIOPin
 
 void GPIO_SetDirection(GPIOPin pin, bool output);
 void GPIO_SetPullup(GPIOPin pin, bool pullup);
+void GPIO_SetPulldown(GPIOPin pin, bool pulldown);
 void GPIO_SetOn(GPIOPin pin);
 void GPIO_SetOff(GPIOPin pin);
 void GPIO_Toggle(GPIOPin pin);
diff --git a/hal/m258ke/gpio.c b/hal/m258ke/gpio.c
index 42b22c1..c8fac93 100644
--- a/hal/m258ke/gpio.c
+++ b/hal/m258ke/gpio.c
@@ -64,13 +64,31 @@ void GPIO_SetPullup(GPIOPin pin, bool pullup)
 	if (pullup)
 	{
 		uint32_t tmp = gpioRegs[pin.port]->PUSEL;
-		tmp &= ~(2UL << 2*pin.pin);
 		tmp |= (1UL << 2*pin.pin);
 		gpioRegs[pin.port]->PUSEL = tmp;
 	}
 	else
 	{
-		gpioRegs[pin.port]->PUSEL &= ~(3UL << 2*pin.pin);
+		gpioRegs[pin.port]->PUSEL &= ~(1UL << 2*pin.pin);
+	}
+}
+
+/** Sets whether an input GPIO pin is pulled down
+ *
+ * @param pin The pin
+ * @param pulldown True if it should be pulled down, false if not
+ */
+void GPIO_SetPulldown(GPIOPin pin, bool pulldown)
+{
+	if (pulldown)
+	{
+		uint32_t tmp = gpioRegs[pin.port]->PUSEL;
+		tmp |= (2UL << 2*pin.pin);
+		gpioRegs[pin.port]->PUSEL = tmp;
+	}
+	else
+	{
+		gpioRegs[pin.port]->PUSEL &= ~(2UL << 2*pin.pin);
 	}
 }