title: Determining port inside the GPIO EXTI Handler
body: <p>How to determine the port from which the interrupt has been generated in the handler? For example, in the EXTI0_IRQHandler how will I determine whether the interrupt was generated through PA0, PB0 or PC0? Is it even possible to handle interrupts from these pins on the same EXTI line (if only one pin generates an interrupt at a time so that there is no confict)?</p>