Diff: main.cpp

Revision:

0:c5bcf643a8b1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Feb 03 21:06:02 2013 +0000
@@ -0,0 +1,32 @@
+#include "mbed.h"
+
+Serial pc(USBTX, USBRX);
+InterruptIn in(p8);
+DigitalOut led(LED1);
+DigitalOut led2(LED2);
+Timer t1;
+
+float t_period = 0;                   // This is the period between interrupts in microseconds
+float t_freq = 0;
+
+void flip(void)
+{
+    led=!led;
+    t_period = t1.read_us();                // Get time since last interrupt
+    t_freq = (1/t_period)*1000000;   // Convert period (in us) to frequency (Hz)
+    t1.reset();                             // Reset timer and wait for next interrupt
+}
+
+int main() {
+    pc.printf("\rStarting frequency counter\n");
+    in.mode(PullDown);              // Set the pin to Pull Down mode.
+    in.rise(&flip);                 // Set up the interrupt for rising edge
+    t1.start();                     // start the timer
+      
+    while (1) {
+        wait_ms(100);
+        led2=!led2;
+        pc.printf("\rfrq is %d Hz\n", (int)t_freq);
+    }
+
+}
\ No newline at end of file