title: Rising and Falling Trigger Edges in HAL_GPIO_EXTI_Callback()
body: <p>I have a digital input <code>GPIO</code> line where I need an interrupt whenever its input changes. In <code>STM32CubeMX</code> I set this pin to an <code>EXTI</code> line and set the interrupt to trigger on both rising and falling edges.</p>
  
  <p>When, in response to either a rising or falling edge the function <code>HAL_GPIO_EXTI_Callback()</code> is called, is there a way to know whether it was a rising or falling edge that triggered the interrupt? Or will it be necessary to call <code>HAL_GPIO_ReadPin()</code> to infer this?</p>
  
  <p>The prototype of the callback is:</p>
  
  <pre><code>void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin);
  </code></pre>