Diff: main.cpp

Revision:

0:c9c3c570d34c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Nov 06 12:43:33 2016 +0000
@@ -0,0 +1,49 @@
+ /*Program Example 9: Metronome. Uses Ticker to set beat rate
+ */
+ #include "mbed.h"
+ #include <stdio.h>
+ Serial pc(USBTX, USBRX);
+ DigitalIn button(PC_13);
+ DigitalIn dir(D4,PullDown);
+ DigitalOut redled(D8); //displays the metronome beat
+ Ticker beat_rate; //define a Ticker, with name “beat_rate”
+ void beat(void);
+ float period (0.5); //metronome period in seconds, initial value 0.5
+ int rate (120); //metronome rate, initial value 120
+ int main()
+ {
+     pc.printf("\r\n");
+     pc.printf("mbed metronome!\r\n");
+     pc.printf("_______________\r\n");
+     period = 1;
+     redled = 1; //diagnostic
+     wait(.1);
+     redled = 0;
+     beat_rate.attach(&beat, period); //initializes the beat rate
+     //main loop checks buttons, updates rates and displays
+     while(1) {
+         if (button ==0) {
+         if (dir)
+         //increase rate by 4
+         rate = rate + 4;
+         else
+         //decrease rate by 4
+         rate = rate - 4;
+     }
+     if (rate > 208) //limit the maximum beat rate to 208
+        rate = 208;
+     if (rate < 40) //limit the minimum beat rate to 40
+        rate = 40;
+     period = 60/rate; //calculate the beat period
+     pc.printf("metronome rate is %i\r", rate);
+     //pc.printf("metronome period is %f\r\n", period); //optional check
+     wait (0.5);
+     }
+ }
+ void beat() //this is the metronome beat
+ {
+     beat_rate.attach(&beat, period); //update beat rate at this moment
+     redled = 1;
+     wait(.1);
+     redled = 0;
+ }
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