void ConfigureUserLED()
{
	// GPIOA clock enable
	RCC->IOPENR = 1;
	GPIOA->MODER &= ~(3 << 10);
	GPIOA->MODER |= (1 << 10);
}

int main()
{
	// Configure PA5 as output
	ConfigureUserLED();

	// TIM3 clock enable
	RCC->APBENR1 |= (1 << 1);

	// Set Prescaler and Auto Reload Register to slow the
	//	processor down so we can see the LED blink.
	// Freq = SYSCLK / ((PSC - 1) * (ARR - 1))
	// Freq = 12MHz / ((12000 - 1) * (100 - 1))
	// Freq = ~10Hz
	TIM3->PSC = 12000;
	TIM3->ARR = 100;

	// Start the timer
	TIM3->CR1 |= 1;

	while(1)
	{
		// Wait for the overflow event to be fired
		while(!(TIM3->SR & TIM_SR_UIF)){}

		// Reset the Update Interrupt Flag
		TIM3->SR &= ~TIM_SR_UIF;

		// Toggle the LED
		GPIOA->ODR ^= (1 << 5);
	}
}