Diff: main.cpp

Revision:

0:e7803aa951be

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Jan 25 14:17:24 2016 +0000
@@ -0,0 +1,41 @@
+#include "mbed.h"
+
+SPI acc(p9,p11,p8); // setup SPI interface on pins 9,11,8. MOSI, MISO, SCK
+
+DigitalOut cs(p10); // use pin 10 as chip select
+
+Serial pc(USBTX, USBRX); // setup USB interface  (change to set up BLE)
+
+char buffer[6]; // raw data array type char
+
+signed short data[3]; // acc data is signed 16 bit from -32,768 to +32,767
+
+float x, y, z; // floating point data
+
+int main() {
+    cs=1;
+    acc.format(8,3); // 8 bit data, Mode 3
+    acc.frequency(2000000); // 2MHz clock rate
+    cs=0;
+    acc.write(0x31); // data format register, select 4 wire mode
+    acc.write(0x0B); // format +/-16g, 0.004g/LSB
+    cs=1;
+    cs=0;
+    acc.write(0x2D); // power ctrl register
+    acc.write(0x08); // measure mode
+    cs=1;
+    while (1) { // infinite loop
+        wait(0.2);
+        cs=0;
+        acc.write(0x80|0x40|0x32); // RW bit high, MB bit high, plus address
+        for (int i = 0;i<=5;i++) {
+            buffer[i]=acc.write(0x00); // read back 6 data bytes
+            }
+        cs=1;
+    data[0] = buffer[1]<<8 | buffer[0]; // combine MSB and LSB
+    data[1] = buffer[3]<<8 | buffer[2];
+    data[2] = buffer[5]<<8 | buffer[4];
+    x=0.004*data[0]; y=0.004*data[1]; z=0.004*data[2]; // convert to floating point
+    pc.printf("x = %+1.2fg\t y = %+1.2fg\t z = %+1.2fg\n\r", x, y,z); //print to screen (change to publish)
+    }
+ }
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