Diff: main.cpp

Revision:

0:0487fe0e0dd5

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Aug 17 00:08:46 2015 +0000
@@ -0,0 +1,81 @@
+#include "mbed.h"
+ 
+//Number of dutycycle steps for output wave
+#define TRI_STEPS          33
+
+//Frequency of output sine in Hz
+#define TRI_OUT_FREQ       1
+               
+//Frequency of Pulse Width Modulated signal in Hz
+#define PWM_FREQ           6600
+
+float tri_duty[TRI_STEPS];
+ 
+//PWM pin
+PwmOut mypwm(D10);
+ 
+//Heartbeat LED
+DigitalOut myled(LED1);
+ 
+//Ticker to update the PWM dutycycle
+Ticker pwm_ticker;
+ 
+//Ticker calls this fucntion to update the PWM dutycycle
+void pwm_duty_updater() {
+  static int idx = 0;
+  mypwm.write(tri_duty[idx]);   // Set the dutycycle % to next value in array
+  idx++;                         // Increment the idx
+  if (idx == TRI_STEPS) idx=0;  // Reset the idx when the end has been reached  
+}
+  
+int main() {
+    float tri[] =    {0,
+                      0.0625,
+                      0.125,
+                      0.1875,
+                      0.25,
+                      0.3125,
+                      0.375,
+                      0.4375,
+                      0.5,
+                      0.5625,
+                      0.625,
+                      0.6875,
+                      0.75,
+                      0.8125,
+                      0.875,
+                      0.9375,
+                      1,
+                      0.9375,
+                      0.875,
+                      0.8125,
+                      0.75,
+                      0.6875,
+                      0.625,
+                      0.5625,
+                      0.5,
+                      0.4375,
+                      0.375,
+                      0.3125,
+                      0.25,
+                      0.1875,
+                      0.125,
+                      0.0625,
+                      0};
+                      
+    for (int i = 0; i < TRI_STEPS; i++)    {
+        tri_duty[i] = tri[i];
+    }
+                      
+    // Set PWM frequency
+    mypwm.period( 1.0f / (float) PWM_FREQ);
+ 
+    // Init the Ticker to call the dutycyle updater at the required interval
+    // The update should be at (SINE_STEPS * SINE_OUT_FREQ) 
+    pwm_ticker.attach(&pwm_duty_updater, 1.0f / (float)(TRI_STEPS * TRI_OUT_FREQ));
+ 
+    while(1){ //infinite loop
+    myled = !myled; 
+    wait(0.5);  
+  }
+}
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