Diff: main.cpp

Revision:

0:6e12cd8b71b4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Nov 22 20:11:48 2018 +0000
@@ -0,0 +1,37 @@
+#include "mbed.h"
+
+SPI acc(D11,D12,D13); // setup SPI interface on pins D11--MOSI>>SDA,D12--MISO>>SDO,D13--SCL
+DigitalOut cs(D10); // use pin 14 as chip select
+
+Serial pc(USBTX, USBRX); // setup USB interface to host terminal
+
+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
+ 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) {
+    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
+ }
+}
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