twowire.lst

T112 MCU源程码,用于T112外接MCU篇程,用来驱动模拟屏

 147   2                                                        Set_SCL_Low;
 148   2                                                        
 149   2                                           }
 150   1                                      
 151   1                                           if(cNum==1)
 152   1                                              Set_SDA_High;
 153   1                                           else
 154   1                                                      Set_SDA_Low;
 155   1                                           //SDA = (cNum==1) 1:0;
 156   1                                           Set_SCL_High;
 157   1                                           while(SCL_Low){};
 158   1                                           for(j = 0; j < TWD_SHORT_TIME; j++)
 159   1                                           { };
 160   1                                      
 161   1                                          Set_SCL_Low;
 162   1                                      
 163   1                                          Set_SDA_High;
 164   1                                          for(j = 0; j < TWD_SHORT_TIME; j++)
 165   1                                          { };
 166   1                                      
 167   1                                          return cRetval;
 168   1                                      }
 169                                          
 170                                          #else
                                              // for fast Two Wire Bus Speed
                                              
                                              void StartCondition(void)
                                              {
                                              //    uCHAR ix;
                                                  uCHAR cTWtrytime=0;
                                              
                                                  while(++cTWtrytime)
C51 COMPILER V7.06   TWOWIRE                                                               03/01/2007 08:05:39 PAGE 4   

                                                  {
                                                      Set_SDA_High;
                                                      Set_SCL_High;        /* make sure two line is release */
                                              
                                                      Set_SDA_Low;
                                              
                                                      if((SCL_High)&&(SDA_Low))
                                                          break;
                                                  }
                                              }
                                              
                                              //----------------------------------------
                                              // P_Condition for TWD protocol
                                              //----------------------------------------
                                              void StopCondition(void)
                                              {
                                              //    uCHAR ix;
                                                  uCHAR cTWtrytime=0;
                                              
                                                  Set_SDA_Low;
                                                  Set_SCL_High;
                                              
                                                  Set_SDA_High;
                                              }
                                              
                                              //--------------------------------------------------
                                              // Send_Byte
                                              //    Send a byte to master with a acknowledge bit
                                              //--------------------------------------------------
                                              uCHAR Send_Byte(uCHAR cData)
                                              {
                                                  uCHAR ix;
                                                  uCHAR cAcknowledge;
                                                  uCHAR cTWtrytime=0;
                                              
                                                  cAcknowledge = 0;
                                              
                                                  for(ix = 0; ix < 8; ix++)
                                                  {
                                                      Set_SCL_Low;
                                                      //        (cData&(1<<(7-ix)))?(Set_SDA_High):(Set_SDA_Low);  /* MSB First */
                                                      if(cData&0x80)Set_SDA_High;
                                                              else Set_SDA_Low;
                                                              cData<<=1;
                                              
                                              
                                                      Set_SCL_High;
                                                  }
                                              
                                                  Set_SCL_Low;
                                                  Set_SDA_High;                /* release data line for acknowledge */
                                                  Set_SCL_High;                /* Send a clock for Acknowledge */
                                              
                                                  if(SDA_High) cAcknowledge = 1; /* No Acknowledge */
                                                  Set_SCL_Low;                   /* Finish Acknoledge */
                                              
                                                  return(cAcknowledge);
                                              }                                                       
                                              
                                              //--------------------------------------------------
                                              // Read_Byte
                                              //    Read a byte from master with a acknowledge bit
C51 COMPILER V7.06   TWOWIRE                                                               03/01/2007 08:05:39 PAGE 5   

                                              //--------------------------------------------------
                                              uCHAR Read_Byte(void)
                                              {
                                                  uCHAR ix, j;
                                                  uCHAR cRetval;
                                                  uCHAR cTWtrytime=0;
                                              
                                              //    cRetval = 0;
                                                  Set_SDA_High;
                                              
                                                  for(ix = 0; ix < 8; ix++)
                                                  {
                                                      Set_SCL_Low;
                                                      for(j = 0; j < TWD_SHORT_TIME; j++)
                                                      { };
                                              
                                                      Set_SCL_High;
                                                      while(SCL_Low)
                                                      { };
                                              
                                                      for(j = 0; j < TWD_SHORT_TIME; j++)
                                                      { };
                                              
                                                              cRetval<<=1;
                                                              if(SDA_High) cRetval++;
                                                      }
                                              
                                                  for(j = 0; j < TWD_SHORT_TIME; j++)
                                                  { };
                                              
                                                  Set_SCL_Low;
                                                  for(j = 0; j < TWD_SHORT_TIME; j++)
                                                  { };
                                              
                                                  return cRetval;
                                              }
                                              
                                              
                                              #endif
 280                                          
 281                                          
 282                                          //--------------------------------------------------
 283                                          // Read Byte to Device
 284                                          //--------------------------------------------------
 285                                          uCHAR I2CReadByte(uCHAR cDevAddr, uCHAR cReg)
 286                                          {
 287   1                                          uCHAR cResult = 0;
 288   1                                      
 289   1                                      
 290   1                                          /* write reg offset */
 291   1                                          StartCondition();
 292   1                                          if(Send_Byte(cDevAddr))
 293   1                                                      return 0;  // Write address
 294   1                                          if(Send_Byte(cReg))
 295   1                                                      return 0;
 296   1                                      
 297   1                                          /* read data */
 298   1                                          StartCondition();
 299   1                                          if (Send_Byte(cDevAddr | 0x01)) // Read address
 300   1                                                      return 0;
 301   1                                          cResult = Read_Byte(1);
 302   1