Diff: acc.cpp

Revision:

3:824764571657

Child:

5:98ad3701ec24

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/acc.cpp	Thu Jan 14 21:35:29 2016 +0000
@@ -0,0 +1,40 @@
+/* Program 7.4: Read ADXL345 accelerometer through SPI.
+Outputs continuously to terminal
+*/
+
+#include "mbed.h"
+
+SPI acc(p11,p12,p13);           //Set up SPI MOSI, MISO, SCL
+DigitalOut cs(p14);             //set up chip select
+Serial pc(USBTX, USBRX);
+char buffer[6];                 //raw filler data
+int16_t data[3];                //16bit twos-compliment integer data
+float x,y,z;                    //set up floats for values to display
+
+int main(){
+    cs=1;                       //initially off
+    acc.format(8,3);            //8bit, mode 3
+    acc.frequency(2000000);     //2MHz
+    cs=0;                       //select
+    acc.write(0x31);            //data format register
+    acc.write(0x0B);            //+/-16g, 0.004g sensitivity
+    cs=1;                       //end transmission
+    cs=0;                       //start new transmission
+    acc.write(0x2D);            //power mode = measure
+    acc.write(0x08);
+    cs=1;
+    
+    
+    while(1){
+        wait(0.2);
+        cs=0;
+        acc.write(0x80|0x40|0x32);      //RW bit high, MB bit high, address
+        for (int i=0;i<=5;i++){buffer[i]=acc.write(0x00);}           //read 6bytes
+        cs=1;
+        data[0]=buffer[1]<<8|buffer[0];             
+        data[1]=buffer[3]<<8|buffer[2];         //combine MSB and LSB
+        data[2]=buffer[5]<<8|buffer[4];
+        x=0.004*data[0];    y=0.004*data[1];    z=0.004*data[2];        //convert to float, actual g value
+        pc.printf("x = %+1.2fg\t y = %+1.2fg\t z = %+1.2fg\n\r", x,y,z);
+    }
+}