Diff: main.cpp

Revision:

0:83a9911ab6ec

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Sep 24 12:31:15 2015 +0000
@@ -0,0 +1,68 @@
+#include "mbed.h"
+
+//Function prototype
+void doSample1Hz();
+
+//Global objects
+Serial pc(USBTX, USBRX);
+AnalogIn POT_ADC_In(A0);
+DigitalOut led(LED1);
+
+#define N 16 
+
+//Shared variables
+volatile static unsigned short sample16 = 0;
+
+unsigned int sum = 0;
+unsigned int count = 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);
+
+    //Set up the ticker - 100Hz
+    t.attach(doSample1Hz, 0.01);
+
+    while(1) {
+
+        //Sleep
+        sleep();
+        
+        //Add new sample to the sum
+        sum += sample16;
+        
+        //Increment the count
+        count++;
+        
+        //Enough to calculate the average?
+        if (count == N) {
+            //Divide sum by 16
+            unsigned short mean = (sum >> 4);   
+            
+            //Display
+            pc.printf("Mean = %hu\n", mean);
+            
+            //Reset sum and count
+            count = sum = 0;
+        }
+ 
+    } //end while(1)
+} //end main
+
+//ISR for the ticker - simply there to perform sampling
+void doSample1Hz()
+{
+    //Toggle on board led
+    led = !led;
+
+    //READ ADC as an unsigned integer.
+    //Shift right 4 bits (this is a 12bit ADC) & store in static global variable
+    sample16 = POT_ADC_In.read_u16() >> 4;
+}
+
+