diff --git a/SHAL/Include/Peripheral/EXT/SHAL_EXTI_CALLBACK.h b/SHAL/Include/Peripheral/EXT/SHAL_EXTI_CALLBACK.h
index 8e69a19..0cf3cc3 100644
--- a/SHAL/Include/Peripheral/EXT/SHAL_EXTI_CALLBACK.h
+++ b/SHAL/Include/Peripheral/EXT/SHAL_EXTI_CALLBACK.h
@@ -22,11 +22,11 @@ extern "C" void EXTI##EXTI_Channel##_IRQHandler(void) {         \
 };
 
 #define DEFINE_MULTI_EXTI_IRQ(EXTI_Channel_Min, EXTI_Channel_Max)                   \
-extern "C" void EXTI##EXTI_Channel_Max##_##EXTI_Channel_Min##_IRQHandler(void) {    \
+extern "C" void EXTI##EXTI_Channel_Min##_##EXTI_Channel_Max##_IRQHandler(void) {    \
     for(uint8_t line = EXTI_Channel_Min; line <= EXTI_Channel_Max; line++){         \
         if (EXTI->PR & (1 << line)) {                                   \
             EXTI->PR |= (1 << line); /*clear flag */                    \
-            auto cb = EXTI_callbacks[line];                                 \
+            auto cb = EXTI_callbacks[line];                                         \
             if (cb) cb();                                                           \
         };                                                                          \
     }                                                                               \
diff --git a/SHAL/Include/Peripheral/GPIO/Reg/SHAL_GPIO_REG_F072xB.h b/SHAL/Include/Peripheral/GPIO/Reg/SHAL_GPIO_REG_F072xB.h
index c76ee80..b05892f 100644
--- a/SHAL/Include/Peripheral/GPIO/Reg/SHAL_GPIO_REG_F072xB.h
+++ b/SHAL/Include/Peripheral/GPIO/Reg/SHAL_GPIO_REG_F072xB.h
@@ -209,7 +209,7 @@ constexpr SHAL_Peripheral_Register getGPIORCCEnable(const GPIO_Key g){
     __builtin_unreachable();
 }
 
-constexpr unsigned int getGPIOPortNumber(const GPIO_Key g){
+constexpr uint32_t getGPIOPortNumber(const GPIO_Key g){
     switch(g) {
         case GPIO_Key::A0:
         case GPIO_Key::A1:
diff --git a/SHAL/Include/Peripheral/UART/SHAL_UART.h b/SHAL/Include/Peripheral/UART/SHAL_UART.h
index ba7ba68..2a6ebfc 100644
--- a/SHAL/Include/Peripheral/UART/SHAL_UART.h
+++ b/SHAL/Include/Peripheral/UART/SHAL_UART.h
@@ -17,13 +17,13 @@ class UART{
 public:
 
     //begins Tx and Usart TODO either modify this function or add a new one that supports Rx
-    void begin(uint32_t baudRate);
+    void begin(uint32_t baudRate) volatile;
 
     //Sends a string
-    void sendString(const char* s);
+    void sendString(const char* s) volatile;
 
     //Sends a char
-    void sendChar(char c);
+    void sendChar(char c) volatile;
 
 private:
 
diff --git a/SHAL/Src/Peripheral/GPIO/SHAL_GPIO.cpp b/SHAL/Src/Peripheral/GPIO/SHAL_GPIO.cpp
index 2783ad4..2c6a2b8 100644
--- a/SHAL/Src/Peripheral/GPIO/SHAL_GPIO.cpp
+++ b/SHAL/Src/Peripheral/GPIO/SHAL_GPIO.cpp
@@ -75,8 +75,9 @@ GPIO& GPIOManager::get(GPIO_Key key, PinMode pinMode) {
 }
 
 void GPIOManager::getInterruptGPIO(GPIO_Key key, TriggerMode triggerMode, EXTICallback callback) {
-    unsigned int gpioPort = getGPIOPortNumber(key);
-    unsigned long gpioPin = getGPIORegister(key).global_offset; //Use existing structs to get offset
+
+    uint32_t gpioPort = getGPIOPortNumber(key);
+    uint32_t gpioPin = getGPIORegister(key).global_offset; //Use existing structs to get offset
 
     if (m_gpios[gpioPort][gpioPin].m_GPIO_KEY == GPIO_Key::INVALID){
         m_gpios[gpioPort][gpioPin] = GPIO(key,PinMode::INPUT_MODE); //Hardcode input mode for interrupt
@@ -112,4 +113,6 @@ void GPIOManager::getInterruptGPIO(GPIO_Key key, TriggerMode triggerMode, EXTICa
 
     //Set callback
     registerEXTICallback(key,callback);
+
+    __enable_irq(); //Enable IRQ just in case
 }
\ No newline at end of file
diff --git a/SHAL/Src/Peripheral/UART/SHAL_UART.cpp b/SHAL/Src/Peripheral/UART/SHAL_UART.cpp
index ee35724..8b653ad 100644
--- a/SHAL/Src/Peripheral/UART/SHAL_UART.cpp
+++ b/SHAL/Src/Peripheral/UART/SHAL_UART.cpp
@@ -41,7 +41,7 @@ UART::UART(const UART_Pair pair) : m_UARTPair(pair){
     *pairUARTEnable.reg |= pairUARTEnable.mask; //Enable UART line
 }
 
-void UART::begin(uint32_t baudRate) {
+void UART::begin(uint32_t baudRate) volatile {
 
     USART_TypeDef* usart = getUARTPair(m_UARTPair).USARTReg;
 
@@ -57,11 +57,11 @@ void UART::begin(uint32_t baudRate) {
 
 }
 
-void UART::sendString(const char *s) {
+void UART::sendString(const char *s) volatile {
     while (*s) sendChar(*s++); //Send chars while we haven't reached end of s
 }
 
-void UART::sendChar(char c) {
+void UART::sendChar(char c) volatile {
 
     USART_TypeDef* usart = getUARTPair(m_UARTPair).USARTReg;
 
diff --git a/SHAL/Src/main.cpp b/SHAL/Src/main.cpp
index 1b880a1..9069cdd 100644
--- a/SHAL/Src/main.cpp
+++ b/SHAL/Src/main.cpp
@@ -4,12 +4,10 @@
 
 volatile GPIO* blueLED = nullptr;
 volatile GPIO* greenLED = nullptr;
+volatile UART* uart2;
 
-extern "C" void EXTI0_1_IRQHandler(void) {
-    if (EXTI->PR & (1 << 0)) {   //Check pending flag
-        EXTI->PR |= (1 << 0);    //Clear it by writing 1
-        greenLED->toggle();
-    }
+void c3Interrupt(){
+    greenLED->toggle();
 }
 
 void tim2Handler(){
@@ -18,11 +16,11 @@ void tim2Handler(){
 
 int main() {
 
-    UART uart2 = getUART(UART_Pair::Tx2A2_Rx2A3);
+    uart2 = &getUART(UART_Pair::Tx2A2_Rx2A3);
 
-    uart2.begin(115200);
+    uart2->begin(115200);
 
-    RCC->AHBENR |= RCC_AHBENR_GPIOBEN;
+    useGPIOAsInterrupt(GPIO_Key::C3,TriggerMode::RISING_EDGE,c3Interrupt);
 
     Timer timer2 = getTimer(Timer_Key::S_TIM2);
 
@@ -34,20 +32,7 @@ int main() {
     timer2.setCallbackFunc(tim2Handler);
     timer2.start();
 
-    RCC->APB2ENR |= RCC_APB2ENR_SYSCFGCOMPEN; //Enable SYSCFG clock (needed for EXTI)
-
-    SYSCFG->EXTICR[0] &= ~SYSCFG_EXTICR1_EXTI0; //Clear EXTI0 mapping
-    SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI0_PB; //Map PA0 -> EXTI0
-
-    EXTI->IMR |= (1 << 0);   //Unmask EXTI0
-    EXTI->RTSR |= (1 << 0);  //Trigger on rising edge
-
-    NVIC_EnableIRQ(EXTI0_1_IRQn); //EXTI lines 0 and 1 share an IRQ vector
-
-    __enable_irq();
-
     while (true) {
     	__WFI();
-        uart2.sendString("Hello\r\n");
     }
 }