diff --git a/STM32/cores/arduino/stm32/USBDevice.cpp b/STM32/cores/arduino/stm32/USBDevice.cpp
index e57d7ed..649614a 100644
--- a/STM32/cores/arduino/stm32/USBDevice.cpp
+++ b/STM32/cores/arduino/stm32/USBDevice.cpp
@@ -40,10 +40,10 @@ void USBDeviceClass::reenumerate() {
       volatile unsigned int i;
 
     #ifdef USB_DISC_PIN
-      pinMode(USB_DISC_PIN, OUTPUT);
-      digitalWrite(USB_DISC_PIN, HIGH);
+      pinModeConst(USB_DISC_PIN, OUTPUT);
+      digitalWriteConst(USB_DISC_PIN, HIGH);
         for(i=0;i<512;i++);
-      digitalWrite(USB_DISC_PIN, LOW);
+      digitalWriteConst(USB_DISC_PIN, LOW);
     #else
       //pinMode(USBDP_PIN, OUTPUT);
       //digitalWrite(USBDP_PIN, LOW);
@@ -51,11 +51,11 @@ void USBDeviceClass::reenumerate() {
       //digitalWrite(USBDP_PIN, HIGH);
 
 
-      pinMode(PA12, OUTPUT);
-      digitalWrite(PA12, LOW);
+      pinModeConst(PA12, OUTPUT);
+      digitalWriteConst(PA12, LOW);
       //HAL_Delay(1000);
       for(i=0;i<1512;i++){};
-      pinMode(PA12, INPUT);
+      pinModeConst(PA12, INPUT);
       //digitalWrite(PA12, HIGH);
       //HAL_Delay(1000);
       for(i=0;i<512;i++){};
diff --git a/STM32/cores/arduino/stm32/stm32_gpio.h b/STM32/cores/arduino/stm32/stm32_gpio.h
index f0597f3..7a52ab5 100644
--- a/STM32/cores/arduino/stm32/stm32_gpio.h
+++ b/STM32/cores/arduino/stm32/stm32_gpio.h
@@ -91,6 +91,65 @@ inline int digitalRead(uint8_t pin) {
     
 }
 
+
+///////////////////////////////
+// The following functions are meant to be used with compile time constant parameters
+
+#define PIN(a, b) { GPIO##a , GPIO_PIN_##b }
+
+static const stm32_port_pin_type variant_pin_list_static[] = {
+  VARIANT_PIN_LIST
+};
+#undef PIN
+
+inline void digitalWriteConst(uint8_t pin, uint8_t value) {
+    HAL_GPIO_WritePin(variant_pin_list_static[pin].port, variant_pin_list_static[pin].pin_mask, value ? GPIO_PIN_SET : GPIO_PIN_RESET);
+}
+
+inline int digitalReadConst(uint8_t pin) {
+    return HAL_GPIO_ReadPin(variant_pin_list_static[pin].port, variant_pin_list_static[pin].pin_mask);
+}
+inline void pinModeConst(uint8_t pin, uint8_t mode) {
+    stm32_port_pin_type port_pin = variant_pin_list_static[pin];
+
+    stm32GpioClockEnable(port_pin.port);
+
+    GPIO_InitTypeDef init;
+
+    init.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
+    init.Pin = port_pin.pin_mask;
+
+    switch ( mode ) {
+      case INPUT:
+        init.Mode = GPIO_MODE_INPUT;
+        init.Pull =  GPIO_NOPULL;
+        break;
+
+      case INPUT_PULLUP:
+        init.Mode = GPIO_MODE_INPUT;
+        init.Pull =  GPIO_PULLUP;
+        break;
+
+      case INPUT_PULLDOWN:
+        init.Mode = GPIO_MODE_INPUT;
+        init.Pull =  GPIO_PULLDOWN;
+        break;
+
+      case OUTPUT:
+        init.Mode = GPIO_MODE_OUTPUT_PP;
+        init.Pull =  GPIO_NOPULL;
+        break;
+
+      default:
+        return;
+        break;
+    }
+
+    HAL_GPIO_Init(port_pin.port, &init);
+
+}
+
+
 #ifdef __cplusplus
 }
 #endif