ADXL.cpp

00001 #include "ADXL.h"
00002 
00003 SPI acc(p11, p12, p13);
00004 DigitalOut cs(p10);
00005 char buffer[6];
00006 int16_t tempData[3];
00007 float x, y, z;
00008 
00009 void accConfig() {
00010     cs=1;                   // initially ADXL345 is not activated
00011     acc.format(8,3);        // 8 bit data, Mode 3
00012     acc.frequency(2000000); // 2MHz clock rate
00013     cs=0;                   //select the device
00014     acc.write(0x31);        // data format register
00015     acc.write(0x0B);        // format +/-16g, 0.004g/LSB
00016     cs=1;                   //end of transmission
00017     cs=0;                   //start a new transmission
00018     acc.write(0x2D);        // power ctrl register
00019     acc.write(0x08);        // measure mode
00020     cs=1;                   // end of transmission
00021 }
00022 
00023 void getAccel(float* data) {
00024         wait(0.2);
00025         cs=0;                           //start a transmission
00026         acc.write(0x80|0x40|0x32);      // RW bit high, MB bit high, plus address
00027         for (int i = 0;i<=5;i++) {
00028             buffer[i]=acc.write(0x00);  // read back 6 data bytes
00029         }
00030         cs=1;                           //end of transmission
00031         tempData[0] = buffer[1] << 8 | buffer[0]; //combine MSB and LSB
00032         tempData[1] = buffer[3] << 8 | buffer[2];
00033         tempData[2] = buffer[5] << 8 | buffer[4];
00034         x = tempData[0]*0.004;
00035         y = tempData[1]*0.004;
00036         z = tempData[2]*0.004;
00037         data[0] = x;
00038         data[1] = y;
00039         data[2] = z;
00040         
00041 }