master.cpp

00001 #include "master.h"
00002  
00003 I2C master (p28,p27);                      //configure pins p27,p28 as I2C master
00004 Serial pc (USBTX,USBRX);
00005 SensorData Sensor;
00006   
00007 void FUNC_I2C_MASTER_MAIN(int command, int slave_address, int iterations)
00008 {
00009     printf("\nmaster entered\n");
00010     int acknowledge1;
00011     int acknowledge2;
00012     uint8_t loopvariable1=1,loopvariable2=0;
00013     int addr = slave_address;
00014     while(loopvariable1)
00015     {
00016 //-------------writing the command to slave--------------------------------------------------------------        
00017         master.frequency(100000);                       //set clock frequency
00018         master.start();                                 //initiating the data transfer
00019         acknowledge2=master.write(addr|0x00);           //addressing the slave to write
00020         if(acknowledge2==1)                             //proceeding further only if slave is addressed
00021         {
00022         acknowledge1=master.write(command);         //sending the command to slave 
00023         if(acknowledge1==1)                             //proceeding further only if sent data is acknowledged   
00024            {
00025                pc.printf("acknowledge1=%d\n",acknowledge1);
00026                loopvariable1=0;                         //if acknowledged, breaking loop in next iteration
00027 //--------------reading data from slave---------------------------------------------------------------          
00028                
00029                     master.frequency(100000);                    //set clock frequency 
00030                     master.start();                              //initiate data transfer 
00031                     acknowledge1 = master.write(addr | 0x01);    //addressing the slave to read
00032                     
00033                     if(acknowledge1==1)                          //proceedong only if slae is addressed
00034                        {  
00035                        while(loopvariable2<iterations)
00036                         { 
00037                           if(loopvariable2%3==0)
00038                             {
00039                               Sensor.voltage[loopvariable2/3] =  receive_byte();              //receiving data if acknowledged
00040                               pc.printf(" voltage%d = %u\n",loopvariable2/3,Sensor.voltage[loopvariable2/3]);
00041                             }
00042                           else if(loopvariable2%3==1)
00043                             {  
00044                               Sensor.current[loopvariable2/3] =  receive_byte();             //receiving data if acknowledged
00045                               pc.printf(" current%d = %u\n",loopvariable2/3, Sensor.current[loopvariable2/3]);
00046                             }
00047                           else if(loopvariable2%3==2)
00048                             {
00049                               Sensor.temp[loopvariable2/3] =  receive_byte();                //receiving data if acknowledged
00050                               pc.printf(" temperature%d = %u\n",loopvariable2/3,Sensor.temp[loopvariable2/3]);
00051                             }
00052                           loopvariable2++;
00053                           
00054                          } //while(loopvariable2<30) 
00055                        }//if(acknowledge1==1)
00056                  
00057               master.stop();
00058            }//if(acknowledge1==1)   
00059         }//if(acknowledge2==1) 
00060      }//while(loopvariable1)
00061    pc.printf("done");
00062 printf("\nMaster exited\n");
00063 }//main
00064  
00065  
00066 //----------------function to read and return the data received-----------------------------------
00067 char receive_byte()                                    
00068 {
00069    
00070     char value;
00071     value = master.read(1);                     
00072     return(value);                              //returning the 4 byte floating point number  
00073 }