keypad.c

《OSEK/VDX汽车电子嵌入式软件编程技术》中光盘的资料

/************************************************
*
*	$Copyright    2001 Joseph J. Lemieux  ALL RIGHTS RESERVED. $
*
*	$Filename: C:\OSEKBook\src\CH15\src\keypad.c $
*
*	Description: Keypad Sample and Control Routines	
*
************************************************/
#ifndef KEYPADC
#define KEYPADC

/************************************************
*
*	Include files
*
************************************************/

#include "typedefs.h"
#include "os.h"
#include "register.h"
#include "mpc555.h"
#include "init.h"
#include "hw.h"
#include "keypad.h"

DeclareTask(ProcessKeyPress);

/************************************************
*
*	Local macros
*
************************************************/

/************************************************
*
*	Local type definitions
*
************************************************/

/************************************************
*
*	Local Function Prototypes
*
************************************************/

/************************************************
*
*	Local Variables
*
************************************************/
UINT8 keyCount=0;
char lastKey = 0;

/************************************************
*
*	Global Variables
*
************************************************/

/************************************************
*
*	Local Constants
*
************************************************/

/************************************************
*
*	Functions
*
************************************************/
/************************************************
*
*   Function:     InitKeypad
*
*   Inputs:       type - type of initialization occurring.
*
*   Outputs:      none
*
*   Returns:      void
*
*   Description:  Initialize the Keypad module
*
************************************************/
void InitKeypad(InitType type)
{
}

/************************************************
*
*   Task:         IOSampleKeypad
*
*   Description:  Samples the keypad and debounces
*                 any keypresses.
*
************************************************/
TASK(IOSampleKeypad)
{
static BOOLEAN keyState = FALSE;
char tempKey;
TaskStateType taskState;

   tempKey = HWGetValue(&KEYPAD);
   if(tempKey == lastKey){
      if(keyCount++ == KEY_DEBOUNCE_TIME){
         --keyCount;
         if(tempKey != 0){
            if(keyState ==  FALSE){
               *keyPressed = tempKey;
               SendMessage(KeyPressMessage,keyPressed);
               keyState = TRUE;
            }
         }
         else{
            keyState = FALSE;
         }
      }
   }
   else{
      keyCount = 0;
      lastKey = tempKey;
   }
   TerminateTask();
}

#endif /* KEYPADC */