switch_wait_timeoutl.c

来自「CODE for embedded C ,hand coding version」· C语言 代码 · 共 72 行

/*--------------------------------------------------------------------*-
  Switch_Wait_TimeoutL.C(v1.00)
  ----------------------------------------------------------------------
  Simple library for processing a switch input
  (Made more reliable by means of a ~10-second timeout)
  -*------------------------------------------------------------------*/
  #include "Main.H"
  #include "Port.H"
  #include "Switch_Wait_TimeoutL.H"
  #include "Delay_T0.H"
  #include "TimeoutL.H"

  /*------------------------------------------------------------------*-
   SWITCH_Init()
   Initialisation function for the switch library
   -*-----------------------------------------------------------------*/

   void SWITCH_Init(void){
    Switch_pin  = 1  ; //Use this pin for input 

    }

  /*------------------------------------------------------------------*-
  SWITCH_Get_Input()
  Reads and debounces  a mechanical switch as follows:
  1.If switch is not pressed ,return SWITCH_NOT_PRESSED
  2.If switch is pressed,wait for DEBOUNCE_PERIOD (in ms)
    a. If switch is not pressed ,return SWITCH_NOT_PRESSED
	b. If switch is pressed,wait(with timeout) for switch to be released.If it
	times out ,then return SWITCH_NOT_PRESSED ; otherwise ,return SWITCH_PRESSED
  See Switch_Wait.H for details of return values;


  -*-------------------------------------------------------------------*/

  bit SWITCH_Get_Input(const tByte DEBOUNCE_PERIOD){
    tByte Return_value= SWITCH_NOT_PRESSED;
	tLong Timeout_loop= LOOP_TIMEOUT_INIT_10000ms;

	if(Switch_pin == 0){
	  //Switch is pressed
	  //Debounce - just wait
	  Delay_T0_Wait(DEBOUNCE_PERIOD);
	  //Check switch again
	  if(Switch_pin ==0 ){
	    //Wait until the switch is released
		//(With TIMEOUT LOOP - 10 seconds)

		while((Switch_pin == 0) && (++Timeout_loop != 0));

		//Check for timeout
		if (Timeout_loop == 0)
		 Return_value = SWITCH_NOT_PRESSED;
		 else
		   Return_value  = SWITCH_PRESSED;


	  }
	}
     //Now finally return switch value
	 return Return_value;
  }


  /*-----------------------------------------------------------------*-
  ---------------------END OF FILE -----------------------------------
  -*-------------------------------------------------------------------*/