Diff: main.cpp

Revision:

0:315c40dcb63f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Sep 24 12:30:54 2015 +0000
@@ -0,0 +1,87 @@
+#include "mbed.h"
+
+//Constants
+#define N 10
+
+//Function Prototype
+void doCaptureSamples();
+float updateAverage(float newSample, float buffer[]);
+
+//Global objects
+Serial pc(USBTX, USBRX);
+
+BusOut binaryOutput(D5, D6, D7);
+AnalogIn POT_ADC_In(A0);
+AnalogIn LDR_ADC_In(A1);
+DigitalOut strobe(D8);
+
+float xPOT[N]; //Aray of potentiometer samples
+float xLDR[N]; //Aray of LDR samples
+
+//These variables hold the next sample
+static float nextLDRSample, nextPOTSample;
+
+//The location of the oldest sample
+static int indexOfOldest=(N-1);
+
+//These variables hold the average values
+float fPOTSum = 0.0;
+float fLDRSum = 0.0;
+
+//The ticker, used to sample data at a fixed rate
+Ticker t;
+
+//Main function
+int main()
+{
+    //Set baud rate to 115200
+    pc.baud(115200);
+
+    //Print header
+    pc.printf("POT,LDR,avPOT, acLDR\n\n");
+
+    //Set up the ticker - 100Hz
+    t.attach(doCaptureSamples, 0.01);
+
+    while(1) {
+
+        //Sleep
+        sleep();
+
+        //Update sums
+        fPOTSum = fPOTSum + nextPOTSample - xPOT[indexOfOldest];
+        fLDRSum = fLDRSum + nextLDRSample - xLDR[indexOfOldest];
+
+        //Write new sample over the oldest
+        xPOT[indexOfOldest] = nextPOTSample;
+        xLDR[indexOfOldest] = nextLDRSample;
+
+        //update positon of oldest sample
+        indexOfOldest = (indexOfOldest==0) ? (N-1) : indexOfOldest-1;
+
+        //Write to terminal via Serial interface
+        int middle = (indexOfOldest - (N/2)) % N;
+        pc.printf("%6.4f,%6.4f,%6.4f,%6.4f\n", xPOT[middle], xLDR[middle], fPOTSum/(float)N, fLDRSum/(float)N);
+
+        //Check the threshold
+        if (fLDRSum > fPOTSum) {
+            binaryOutput = 0;   //Binary 000
+        } else {
+            binaryOutput = 7;   //Binary 111
+        }
+
+    } //end while(1)
+} //end main
+
+//ISR for the ticker - simply there to perform sampling
+void doCaptureSamples()
+{
+    //Toggle digital out
+    strobe = !strobe;
+
+    //READ ADC - store in static globals
+    //(static globals are shared with all functions in the same C or CPP file)
+    nextLDRSample = LDR_ADC_In;
+    nextPOTSample = POT_ADC_In;
+}
+