pc_io_t2.lst

时间触发嵌入式系统设计模式:使用8051系列微控制器开发可靠应用

C51 COMPILER V6.10  PC_IO_T2                                                               04/18/2001 16:08:41 PAGE 1   


C51 COMPILER V6.10, COMPILATION OF MODULE PC_IO_T2
OBJECT MODULE PLACED IN .\PC_IO_T2.OBJ
COMPILER INVOKED BY: C:\KEIL\C51\BIN\C51.EXE .\PC_IO_T2.c OPTIMIZE(6,SIZE) BROWSE DEBUG OBJECTEXTEND

stmt level    source

   1          /*------------------------------------------------------------------*-
   2          
   3             PC_IO_T2.C (v1.01)
   4          
   5            ------------------------------------------------------------------
   6          
   7             PC link library. Bidirectional. T2 used for baud rate generation.
   8          
   9             Uses the USART, and Pins 3.1 (Tx) and 3.0 (Rx) 
  10          
  11             See text for details (Chapter 18).
  12          
  13          
  14             COPYRIGHT
  15             ---------
  16          
  17             This code is from the book:
  18          
  19             PATTERNS FOR TIME-TRIGGERED EMBEDDED SYSTEMS by Michael J. Pont 
  20             [Pearson Education, 2001; ISBN: 0-201-33138-1].
  21          
  22             This code is copyright (c) 2001 by Michael J. Pont.
  23           
  24             See book for copyright details and other information.
  25          
  26          -*------------------------------------------------------------------*/
  27          
  28          #include "Main.h"
  29          #include "PC_IO_T2.h"
  30          
  31          // ------ Public variable declarations -----------------------------
  32          
  33          extern tByte In_read_index_G;     
  34          extern tByte In_waiting_index_G;  
  35          
  36          extern tByte Out_written_index_G;  
  37          extern tByte Out_waiting_index_G;  
  38          
  39          /*------------------------------------------------------------------*-
  40          
  41            PC_LINK_IO_Init_T2()
  42          
  43            This version uses T2 for baud rate generation.
  44          
  45          -*------------------------------------------------------------------*/
  46          void PC_LINK_IO_Init_T2(const tWord BAUD_RATE)
  47             {
  48   1         tWord RCAP2;
  49   1      
  50   1         PCON &= 0x7F;   // Set SMOD bit to 0 (don't double baud rates)
  51   1      
  52   1         //  Receiver enabled.
  53   1         //  8-bit data, 1 start bit, 1 stop bit, 
  54   1         //  Variable baud rate (asynchronous)
  55   1         //  Receive flag will only be set if a valid stop bit is received
C51 COMPILER V6.10  PC_IO_T2                                                               04/18/2001 16:08:41 PAGE 2   

  56   1         //  Set TI (transmit buffer is empty)
  57   1         SCON = 0x72;
  58   1      
  59   1         // T2 used for baud rate generation.
  60   1         // Gives accurate baud rates, even at 12 MHz, etc...
  61   1         T2CON = 0x34; // Load timer 2 control register
  62   1         T2MOD = 0x00; // Load timer 2 mode register
  63   1         ET2   = 0;
  64   1      
  65   1         // Typically, as a timer, T2  would increment at fOSC /12. 
  66   1         // As a baud rate generator, it increments at fOSC /2. 
  67   1         //
  68   1         // The baud rate (Mode 1 or 3) is given by the formula:
  69   1         //
  70   1         // Baud rate = fOSC /(32 * [65536 - (RCAP2H, RCAP2L)])
  71   1         //
  72   1         // This allows us to do the following:
  73   1         RCAP2  = 65536 - (tWord)((tLong)OSC_FREQ/((tLong)32 * BAUD_RATE));
  74   1         RCAP2H = RCAP2 / 256;
  75   1         TH2    = RCAP2H;
  76   1         RCAP2L = RCAP2 % 256;
  77   1         TL2    = RCAP2L;
  78   1      
  79   1         TR2   = 1;  // Start timer 2
  80   1      
  81   1         TI = 1;     // Send first character (dummy)
  82   1      
  83   1         // Set up the buffers for reading and writing
  84   1         In_read_index_G = 0;
  85   1         In_waiting_index_G = 0;
  86   1         Out_written_index_G = 0;
  87   1         Out_waiting_index_G = 0;
  88   1      
  89   1         PC_LINK_IO_Write_String_To_Buffer("Serial OK\n");
  90   1      
  91   1         // Interrupt *NOT* enabled
  92   1         ES = 0;
  93   1         }
  94          
  95          /*------------------------------------------------------------------*-
  96            ---- END OF FILE -------------------------------------------------
  97          -*------------------------------------------------------------------*/


MODULE INFORMATION:   STATIC OVERLAYABLE
   CODE SIZE        =     84    ----
   CONSTANT SIZE    =     11    ----
   XDATA SIZE       =   ----    ----
   PDATA SIZE       =   ----    ----
   DATA SIZE        =   ----    ----
   IDATA SIZE       =   ----    ----
   BIT SIZE         =   ----    ----
END OF MODULE INFORMATION.


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