title: Implicit declaration function
body: <p>I have decleared a function in a header file and intialized it in .c file.
  But when ich call that function in the main file i get a warning that says:
  implicit declaration of function.
  header file:</p>
  <p>void HCSR04_Read(void);
  initialization in .c file:</p>
  <pre><code>void HCSR04_Read(void)
  </code></pre>
  <p>{
  HAL_GPIO_WritePin(TRIG_PORT, TRIG_PIN, PIN_SET);    //Pull the TRIG pin HIGH
  delay(10);   //Wait 10 us
  HAL_GPIO_WritePin(TRIG_PORT, TRIG_PIN, PIN_RESET);   //Pull th eTRIG pin LOW
  __HAL_TIM_ENABLE_IT(&amp;htim1, TIM_IT_CC1);
  }</p>
  <p>I had included tha header in the main file.
  Any suggestions?</p>