Diff: main.cpp

Revision:

0:d7c850cdbc39

Child:

1:733a0de4d34c

diff -r 000000000000 -r d7c850cdbc39 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri May 24 21:49:35 2013 +0000
@@ -0,0 +1,46 @@
+/*Program Example 9.10: Metronome. Uses Ticker to set beat rate
+                                                                       */            
+#include "mbed.h"
+#include <stdio.h>
+Serial pc(USBTX, USBRX);
+DigitalIn up_button(p5);
+DigitalIn down_button(p6);
+DigitalOut redled(p19);             //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, inital 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);  //initialises the beat rate 
+  //main loop checks buttons, updates rates and displays
+  while(1){
+    if (up_button ==1)   //increase rate by 4
+      rate = rate + 4;
+    if (down_button ==1)   //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;
+  }
+