C51 COMPILER V6.10  PWM_SOFT                                                               03/16/2001 06:57:55 PAGE 1   


C51 COMPILER V6.10, COMPILATION OF MODULE PWM_SOFT
OBJECT MODULE PLACED IN .\PWM_SOFT.OBJ
COMPILER INVOKED BY: C:\KEIL\C51\BIN\C51.EXE .\PWM_SOFT.C OPTIMIZE(6,SPEED) BROWSE DEBUG OBJECTEXTEND

stmt level    source

   1          /*------------------------------------------------------------------*-
   2          
   3             PWM_SOFT.C (v1.00)
   4          
   5            ------------------------------------------------------------------
   6          
   7             Simple 'Software PWM' library.
   8          
   9             See Chapter 33 for details.
  10          
  11          
  12             COPYRIGHT
  13             ---------
  14          
  15             This code is from the book:
  16          
  17             PATTERNS FOR TIME-TRIGGERED EMBEDDED SYSTEMS by Michael J. Pont 
  18             [Pearson Education, 2001; ISBN: 0-201-33138-1].
  19          
  20             This code is copyright (c) 2001 by Michael J. Pont.
  21           
  22             See book for copyright details and other information.
  23          
  24          -*------------------------------------------------------------------*/
  25          
  26          #include "Main.h"
  27          #include "Port.h"
  28          
  29          #include "2_01_12g.h"
  30          #include "PWM_Soft.h"
  31          
  32          // Comment out this line if test function is NOT required
  33          #define PWM_test
  34          
  35          // ------ Public variable definitions ------------------------------
  36          
  37          // Set this variable to the required PWM value
  38          tByte PWM_new_G;
  39          
  40          // ------ Private constants ----------------------------------------
  41          
  42          #define PWM_ON 0
  43          #define PWM_OFF 1
  44          
  45          // ------ Private variables ----------------------------------------
  46          
  47          // The PWM counter
  48          static tWord PWM_position_G;
  49          static tByte PWM_G;
  50          
  51          /*------------------------------------------------------------------*-
  52          
  53            PWM_Soft_Init()
  54          
  55            Prepares some of the key PWM variables.
C51 COMPILER V6.10  PWM_SOFT                                                               03/16/2001 06:57:55 PAGE 2   

  56          
  57          -*------------------------------------------------------------------*/
  58          void PWM_Soft_Init(void)
  59             {
  60   1         // Init the main variable
  61   1         PWM_new_G = 0;
  62   1         PWM_position_G = 0;
  63   1         PWM_pin = PWM_OFF;
  64   1         }
  65          
  66          /*------------------------------------------------------------------*-
  67          
  68            PWM_Soft_Update()
  69          
  70            The key PWM function.  Schedule as rapidle as possible.
  71          
  72          -*------------------------------------------------------------------*/
  73          void PWM_Soft_Update(void)
  74             {
  75   1         // Have we reached the end of the current PWM cycle?
  76   1         if (++PWM_position_G >= PWM_PERIOD)
  77   1            {
  78   2            // Reset the PWM position counter
  79   2            PWM_position_G = 0;
  80   2      
  81   2            // Update the PWM control value
  82   2            PWM_G = PWM_new_G; 
  83   2      
  84   2            // Set the PWM output to OFF
  85   2            PWM_pin = PWM_OFF;
  86   2      
  87   2            return;
  88   2            }
  89   1      
  90   1         // We are in a PWM cycle
  91   1         if (PWM_position_G < PWM_G)
  92   1            {
  93   2            PWM_pin = PWM_ON;
  94   2            }
  95   1         else
  96   1            {
  97   2            PWM_pin = PWM_OFF;
  98   2            }
  99   1         }
 100          
 101          /*------------------------------------------------------------------*-
 102          
 103            PWM_Soft_Test()
 104          
 105            To test the PWM library, this function is called once every 
 106            five seconds, to update the PWM settings.
 107          
 108            NOTE:
 109            In a real application, this function will be replaced by a user-
 110            defined function for setting brightness, speed, etc.
 111          
 112          -*------------------------------------------------------------------*/
 113          #ifdef PWM_test
 114          void PWM_Soft_Test(void)
 115             {
 116   1         if (++PWM_new_G >= PWM_PERIOD)
 117   1            {
C51 COMPILER V6.10  PWM_SOFT                                                               03/16/2001 06:57:55 PAGE 3   

 118   2            PWM_new_G = 0;
 119   2            }
 120   1         }
 121          #endif
 122          
 123          /*------------------------------------------------------------------*-
 124            ---- END OF FILE -------------------------------------------------
 125          -*------------------------------------------------------------------*/
 126          


MODULE INFORMATION:   STATIC OVERLAYABLE
   CODE SIZE        =     68    ----
   CONSTANT SIZE    =   ----    ----
   XDATA SIZE       =   ----    ----
   PDATA SIZE       =   ----    ----
   DATA SIZE        =      4    ----
   IDATA SIZE       =   ----    ----
   BIT SIZE         =   ----    ----
END OF MODULE INFORMATION.


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