main.cpp

00001 
00002 // Read from I2C slave at address 0x62
00003 
00004 #include "mbed.h"
00005 
00006 I2C i2c(p28, p27);
00007 Serial pc(USBTX, USBRX);
00008 DigitalOut myled(LED2);
00009 LocalFileSystem local("local");             // Create the local filesystem under the name "local"
00010 
00011 
00012 int main()
00013 {
00014     unsigned int loop = 1;
00015     unsigned loopCount = 1;
00016     int address = 0x90;
00017     char RXdata[2];
00018     char TXdata[2];
00019     float temperature = 0;
00020     time_t seconds = 0;
00021     
00022     //Hello splash screen
00023     printf("\r\n\nmbeb Temperature logger V0.1\r\nBy Paul J clarke MIET\r\n13th Oct 2010\r\n\n");
00024     
00025     //clear serial buffer
00026     while( pc.readable() );
00027     
00028     //Configure sensor at 0.0625'C steps
00029     TXdata[0] = 0x01;
00030     TXdata[1] = 0x60;
00031     i2c.write(address, TXdata, 2);
00032     //Set dat for reading temperature
00033     TXdata[0] = 0x00;
00034     myled = 0;
00035     
00036     // Opens the root directory of the local file system
00037     printf("Files on mbed\r\n");
00038     DIR *d = opendir("/local");
00039     struct dirent *p;
00040     while((p = readdir(d)) != NULL)
00041     {                                         // Print the names of the files in the local file system
00042       printf("%s\n\r", p->d_name);            // to stdout (USB Serial).
00043     }
00044     closedir(d);
00045     printf("\n");
00046     
00047     // Removes the file "out.txt" from the local file system
00048     remove("/local/log.csv");
00049     // Open "log.csv" on the local file system for writing
00050     FILE *fp = fopen("/local/log.csv", "w");
00051    
00052     //reset time to zero
00053     set_time(0);
00054    
00055     //Send headers to csv file
00056     fprintf(fp, "Time_Seconds,Temperature_C\r");
00057    
00058     //main loop
00059     while(loop)
00060     {
00061         //toggle LED to show we are running
00062         myled = !myled;
00063         //set I2C device to point at temperature registor
00064         i2c.write(address, TXdata, 1);
00065         //read two bytes of raw data back
00066         i2c.read(address, RXdata, 2);
00067         //generate floating point number from raw data recived
00068         temperature = (((float)RXdata[1]) / 256) + RXdata[0];
00069         //stream temperature to USB serial port
00070         printf("Temperature = %.4f'C     Data Point = %d     \r", temperature, loopCount);
00071         //get time in seconds
00072         seconds = time(NULL);
00073         //and save to log file
00074         fprintf(fp, "%d,%.4f\n", seconds, temperature);
00075         //wait 250ms - time for ADC in temp sensor to re calculate new value
00076         wait(1);
00077      
00078         //inc loop counter
00079         loopCount++;
00080         
00081         if( pc.readable() || loopCount==1200 ) //1200 = 5 min's of loggin time
00082         {
00083             loop = 0;
00084         }
00085     }
00086     printf("\r\n\n Finished...\r\nTotal data points = %d\r\n", (loopCount-1));
00087     fclose(fp);
00088 
00089     while(1); //HALT
00090     
00091 }