switch_count.lst

Embedded C 这本书的范例光碟程式

C51 COMPILER V6.21  SWITCH_COUNT                                                           01/23/2002 17:21:00 PAGE 1   


C51 COMPILER V6.21, COMPILATION OF MODULE SWITCH_COUNT
OBJECT MODULE PLACED IN Switch_count.OBJ
COMPILER INVOKED BY: C:\KEIL\C51\BIN\C51.EXE Switch_count.c OPTIMIZE(6,SPEED) BROWSE DEBUG OBJECTEXTEND

stmt level    source

   1          /*------------------------------------------------------------------*-
   2          
   3             Switch_count.C (v1.00)
   4          
   5            ------------------------------------------------------------------
   6          
   7             A 'goat counting' program for the 8051 (see text for details...).
   8          
   9          
  10             COPYRIGHT
  11             ---------
  12          
  13             This code is associated with the book:
  14          
  15             EMBEDDED C by Michael J. Pont 
  16             [Pearson Education, 2002: ISBN: 0-201-79523-X].
  17          
  18             This code is copyright (c) 2001 by Michael J. Pont.
  19           
  20             See book for copyright details and other information.
  21          
  22          -*------------------------------------------------------------------*/
  23          
  24          #include <reg52.h>
  25          
  26          // Connect switch to this pin
  27          sbit Switch_pin = P1^0;
  28          
  29          // Display count (binary) on this port
  30          #define Count_port P3
  31          
  32          // Return values from Switch_Get_Input()
  33          #define SWITCH_NOT_PRESSED (bit) 0 
  34          #define SWITCH_PRESSED (bit) 1 
  35          
  36          // Function prototypes
  37          void SWITCH_Init(void);
  38          bit  SWITCH_Get_Input(const unsigned char); 
  39          void DISPLAY_COUNT_Init(void);
  40          void DISPLAY_COUNT_Update(const unsigned char);
  41          void DELAY_LOOP_Wait(const unsigned int);
  42          
  43          /* ---------------------------------------------------------------- */
  44          void main(void)
  45             {
  46   1         unsigned char Switch_presses = 0;
  47   1      
  48   1         // Init functions
  49   1         SWITCH_Init();
  50   1         DISPLAY_COUNT_Init();
  51   1        
  52   1         while(1) 
  53   1            {
  54   2            if (SWITCH_Get_Input(30) == SWITCH_PRESSED)
  55   2               {
C51 COMPILER V6.21  SWITCH_COUNT                                                           01/23/2002 17:21:00 PAGE 2   

  56   3               Switch_presses++;
  57   3               }
  58   2             
  59   2            DISPLAY_COUNT_Update(Switch_presses);
  60   2            }
  61   1         }
  62          
  63          /*------------------------------------------------------------------*-
  64          
  65            SWITCH_Init()
  66          
  67            Initialization function for the switch library.
  68          
  69          -*------------------------------------------------------------------*/
  70          void SWITCH_Init(void)
  71             {
  72   1         Switch_pin = 1; // Use this pin for input
  73   1         }
  74          
  75          /*------------------------------------------------------------------*-
  76            
  77            SWITCH_Get_Input()
  78          
  79            Reads and debounces a mechanical switch as follows:
  80          
  81            1. If switch is not pressed, return SWITCH_NOT_PRESSED.
  82          
  83            2. If switch is pressed, wait for DEBOUNCE_PERIOD (in ms).
  84               a. If switch is not pressed, return SWITCH_NOT_PRESSED. 
  85               b. If switch is pressed, wait (indefinitely) for
  86                  switch to be released, then return SWITCH_PRESSED
  87          
  88            See Switch_Wait.H for details of return values.
  89            
  90          -*------------------------------------------------------------------*/
  91          bit SWITCH_Get_Input(const unsigned char DEBOUNCE_PERIOD)
  92             {
  93   1         bit Return_value = SWITCH_NOT_PRESSED;
  94   1      
  95   1         if (Switch_pin == 0)
  96   1            {
  97   2            // Switch is pressed
  98   2            
  99   2            // Debounce - just wait...
 100   2            DELAY_LOOP_Wait(DEBOUNCE_PERIOD);
 101   2      
 102   2            // Check switch again
 103   2            if (Switch_pin == 0)
 104   2               {
 105   3               // Wait until the switch is released.
 106   3               while (Switch_pin == 0);
 107   3               Return_value = SWITCH_PRESSED;
 108   3               }
 109   2            }
 110   1         
 111   1         // Now (finally) return switch value
 112   1         return Return_value;
 113   1         }
 114          /*------------------------------------------------------------------*-
 115          
 116            DISPLAY_COUNT_Init()
 117          
C51 COMPILER V6.21  SWITCH_COUNT                                                           01/23/2002 17:21:00 PAGE 3   

 118            Initialization function for the DISPLAY COUNT library.
 119          
 120          -*------------------------------------------------------------------*/
 121          void DISPLAY_COUNT_Init(void)
 122             {
 123   1         Count_port = 0x00;
 124   1         }
 125          
 126          /*------------------------------------------------------------------*-
 127          
 128            DISPLAY_COUNT_Update()
 129          
 130            Simple function to display tByte data (COUNT) 
 131            on LEDs connected to port (Count_Port)
 132          
 133          -*------------------------------------------------------------------*/
 134          void DISPLAY_COUNT_Update(const unsigned char COUNT)
 135             {
 136   1         Count_port = COUNT;
 137   1         } 
 138          
 139          /*------------------------------------------------------------------*-
 140          
 141            DELAY_LOOP_Wait()
 142          
 143            Delay duration varies with parameter.  
 144          
 145            Parameter is, *ROUGHLY*, the delay, in milliseconds,
 146            on 12MHz 8051 (12 osc cycles).
 147          
 148            You need to adjust the timing for your application!
 149          
 150          -*------------------------------------------------------------------*/
 151          void DELAY_LOOP_Wait(const unsigned int DELAY_MS)
 152             {
 153   1         unsigned int x, y;
 154   1      
 155   1         for (x = 0; x <= DELAY_MS; x++)
 156   1            {
 157   2            for (y = 0; y <= 120; y++);
 158   2            }
 159   1         }
 160          
 161          
 162          /*------------------------------------------------------------------*-
 163            ---- END OF FILE -------------------------------------------------
 164          -*------------------------------------------------------------------*/


MODULE INFORMATION:   STATIC OVERLAYABLE
   CODE SIZE        =     89    ----
   CONSTANT SIZE    =   ----    ----
   XDATA SIZE       =   ----    ----
   PDATA SIZE       =   ----    ----
   DATA SIZE        =   ----       1
   IDATA SIZE       =   ----    ----
   BIT SIZE         =   ----       1
END OF MODULE INFORMATION.


C51 COMPILATION COMPLETE.  0 WARNING(S),  0 ERROR(S)