Diff: main.cpp

Revision:

0:ac874e417fac

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Feb 13 16:11:47 2015 +0000
@@ -0,0 +1,123 @@
+
+//magnetometer V1.3
+
+#include "mbed.h"
+#include "SPI.h"
+#include "math.h"
+#include "stdlib.h"
+Serial pc(USBTX,USBRX);
+SPI spi(PTD6,PTD7,PTD5);  //MOSI,MISO,SCLK
+DigitalOut SSN_MAG(PTD4);  //SLAVE SELECT
+InterruptIn DRDY(PTD2);
+Timeout tr_mag;
+uint8_t trflag_mag;
+void trsub_mag();
+int a;
+//void end();
+
+void trsub_mag()
+{
+  trflag_mag=0;
+}  
+  
+void func()
+{
+   // a=1;
+    //wait_ms(100);
+    SSN_MAG=0;
+    spi.write(0xc9);                  //command  byte for retrieving data
+    //printf("\n\rahoy\n\r");
+    unsigned char axis;
+    float Bnewvalue[3]={0.0,0.0,0.0};
+    int32_t Bvalue[3]={0,0,0}; 
+    int32_t a= pow(2.0,24.0);
+    int32_t b= pow(2.0,23.0);
+ 
+    for(axis=0;axis<3;axis++)
+    {
+        Bvalue[axis]=spi.write(0x00)<<16;    //MSB 1 is send first 
+        wait_ms(100);
+        Bvalue[axis]|=spi.write(0x00)<<8;    //MSB 2 is send next
+        wait_ms(100);
+        Bvalue[axis]|=spi.write(0x00);       //LSB is send.....total length is 24 bits(3*8bits)...which are appended to get actual bit configuration
+  
+   
+        if((Bvalue[axis]&b)==b)              
+        {
+            Bvalue[axis]=Bvalue[axis]-a;   //converting 2s complement to  signed decimal
+
+        }
+        Bnewvalue[axis]=(float)Bvalue[axis]*22.0*pow(10.0,-3.0);  //1 LSB=(22nT)...final value of field obtained in micro tesla
+  
+        wait_ms(100);
+        pc.printf("\t%f\n",Bnewvalue[axis]);
+
+    }
+    SSN_MAG=1;
+}
+
+
+void FUNC_ACS_MAGNETOMETER_INIT();
+void FUNC_ACS_MAGNETOMETER_EXECUTE();
+
+void main()
+{
+
+DRDY.rise(&func);
+FUNC_ACS_MAGNETOMETER_INIT();
+while(1)
+{
+
+pc.printf("start\n");
+wait(2);
+FUNC_ACS_MAGNETOMETER_EXECUTE();
+
+} 
+}
+ 
+ void FUNC_ACS_MAGNETOMETER_INIT()
+ {
+   
+  SSN_MAG=1;                                    //pin is disabled
+  spi.format(8,0);                         //   8bits,Mode 0
+  spi.frequency(100000);                   //clock frequency
+  
+  SSN_MAG=0;                                   // Selecting pin
+  wait_ms(100);                            //accounts for delay.can be minimised.
+  
+  spi.write(0x83);                      //
+  
+  wait_ms(100);              
+  
+  unsigned char i;
+  for(i=0;i<3;i++)//initialising values.
+      {
+         spi.write(0x00);              //MSB of X,y,Z
+         spi.write(0xc8);             //LSB of X,Y,z;pointer increases automatically.
+        }
+   SSN_MAG=1;
+ 
+}
+
+void FUNC_ACS_MAGNETOMETER_EXECUTE()
+{
+    SSN_MAG=0;                                //enabling slave to measure the values
+    wait_ms(100);
+    spi.write(0x82);                     //initiates measurement
+    wait_ms(100);
+    spi.write(0x01);                   //selecting x,y and z axes, measurement starts now
+    SSN_MAG=1;
+  
+
+    trflag_mag=1;
+    tr_mag.attach(&trsub_mag,1);
+ //a=0;
+// while(trflag_mag)
+ //{
+ 
+ //if(a==1)
+ 
+// }
+    pc.printf("exit");
+ 
+}
\ No newline at end of file