Diff: main.cpp

Revision:

0:508f6e503222

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Mar 07 12:20:07 2017 +0000
@@ -0,0 +1,44 @@
+#include "mbed.h"
+
+DigitalOut myled(LED1);
+AnalogOut Aout(p18);
+Ticker tick1;
+//Note in this case could reconstruct at known frequency using timer(ticker)
+//125 us ticker gives us 8KHz reconstruction
+//8 samples/period means frequency should be 1KHz
+//works perfectly
+
+
+
+
+unsigned short n=0;
+#define pi 3.1415192
+#define N 8                 //Numebr of samples in one period 
+#define w_hat 2*pi/N          //Normalised radian frequency               
+float sine1 [N];              //contains sine wave sample values
+
+void output_sample(void);
+void init_sine_array(void);
+
+int main() {
+    init_sine_array();
+    tick1.attach_us(&output_sample,3);    //125 us is 8Khz    //limit is 3us which means ~333KHz max fs
+    while(1) {     
+    }
+}
+
+void output_sample(void)
+{
+    Aout = sine1[n];
+    n=(n+1)%N;
+}
+
+void init_sine_array(void)
+{
+    unsigned short n = 0;
+    for (n=0;n<N;n++)
+    {
+        sine1[n] = 0.5 + 0.5*sin(n*w_hat);   //note the 0.5 V of offset since DAC outputs voltage between 0 and 3.3V
+    }
+    
+ }