Fabio Fumi / Mbed 2 deprecated Speaker_test

Basic speaker testing on a STM32L053R8 board. Based on other examples and improved using commands sent from PC over serial-USB (t=Tone, s=Sweep, p=Police, h=Song, space=Exit). A small 8-Ohm speaker directly plugged on GND/PA_0 (PWM out) makes a low but clearly audible sound.

Dependencies:   mbed

main.cpp@0:59717cf94c6a, 2015-01-09 (annotated)

Committer:
ffxx68
Date:
Fri Jan 09 17:46:14 2015 +0000
Revision:
0:59717cf94c6a
Child:
1:7fdec2560f78
improved using serial commands

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ffxx68 0:59717cf94c6a 1 #include "mbed.h"
ffxx68 0:59717cf94c6a 2
ffxx68 0:59717cf94c6a 3 // Notes
ffxx68 0:59717cf94c6a 4 #define A4 440
ffxx68 0:59717cf94c6a 5 #define B4b 446
ffxx68 0:59717cf94c6a 6 #define C4 261
ffxx68 0:59717cf94c6a 7 #define C4_1 130
ffxx68 0:59717cf94c6a 8 #define C5 523
ffxx68 0:59717cf94c6a 9 #define D4 293
ffxx68 0:59717cf94c6a 10 #define D4b 277
ffxx68 0:59717cf94c6a 11 #define E4 329
ffxx68 0:59717cf94c6a 12 #define F4 349
ffxx68 0:59717cf94c6a 13 #define G4 392
ffxx68 0:59717cf94c6a 14
ffxx68 0:59717cf94c6a 15 const int notes[] = {C4_1,C4,D4,C4,F4,E4,C4_1,C4,D4,C4,G4,F4,C4_1,C4,C5,A4,F4,E4,D4,B4b,B4b,A4,F4,G4,F4};
ffxx68 0:59717cf94c6a 16 const int intervals[] = {4, 4, 8, 8, 8, 10, 4, 4, 8, 8, 8, 10, 4, 4, 8, 8, 8, 8, 8, 4, 4, 8, 8, 8, 12};
ffxx68 0:59717cf94c6a 17
ffxx68 0:59717cf94c6a 18 // speaker sound effect demo using PWM hardware output
ffxx68 0:59717cf94c6a 19 PwmOut speaker(PA_0);
ffxx68 0:59717cf94c6a 20 // serail port to PC (over USB)
ffxx68 0:59717cf94c6a 21 Serial pc(USBTX, USBRX); // tx, rx
ffxx68 0:59717cf94c6a 22
ffxx68 0:59717cf94c6a 23 int main()
ffxx68 0:59717cf94c6a 24 {
ffxx68 0:59717cf94c6a 25 int i;
ffxx68 0:59717cf94c6a 26 char c = 0;
ffxx68 0:59717cf94c6a 27
ffxx68 0:59717cf94c6a 28 // Intro ( ta-dah @ 500Hz )
ffxx68 0:59717cf94c6a 29 speaker.period(1.0/500.0); // 500hz period
ffxx68 0:59717cf94c6a 30 speaker =0.5; //50% duty cycle - max volume
ffxx68 0:59717cf94c6a 31 wait(.05);
ffxx68 0:59717cf94c6a 32 speaker=0.0; // turn off audio
ffxx68 0:59717cf94c6a 33 wait(.05);
ffxx68 0:59717cf94c6a 34 speaker =0.5; //50% duty cycle - max volume
ffxx68 0:59717cf94c6a 35 wait(.5);
ffxx68 0:59717cf94c6a 36 speaker=0.0; // turn off audio
ffxx68 0:59717cf94c6a 37
ffxx68 0:59717cf94c6a 38 pc.printf (" \n");
ffxx68 0:59717cf94c6a 39 pc.printf ("t=Tone, s=Sweep, p=Police, h=Song\n");
ffxx68 0:59717cf94c6a 40
ffxx68 0:59717cf94c6a 41 while(c != ' ') {
ffxx68 0:59717cf94c6a 42
ffxx68 0:59717cf94c6a 43 c=pc.getc();
ffxx68 0:59717cf94c6a 44 pc.printf("%c",c);
ffxx68 0:59717cf94c6a 45 wait(.1);
ffxx68 0:59717cf94c6a 46
ffxx68 0:59717cf94c6a 47 switch (c)
ffxx68 0:59717cf94c6a 48 {
ffxx68 0:59717cf94c6a 49 case 't':
ffxx68 0:59717cf94c6a 50 pc.printf ("Tone...\n");
ffxx68 0:59717cf94c6a 51 // generate a short 150Hz tone using PWM hardware output
ffxx68 0:59717cf94c6a 52 // something like this can be used for a button click effect for feedback
ffxx68 0:59717cf94c6a 53 speaker =0.25; //25% duty cycle - mid range volume
ffxx68 0:59717cf94c6a 54 for (i=0; i<10; i++) {
ffxx68 0:59717cf94c6a 55 speaker.period(1.0/150.0); // 500hz period
ffxx68 0:59717cf94c6a 56
ffxx68 0:59717cf94c6a 57 wait(.02);
ffxx68 0:59717cf94c6a 58 }
ffxx68 0:59717cf94c6a 59 speaker=0.0; // off
ffxx68 0:59717cf94c6a 60 break;
ffxx68 0:59717cf94c6a 61
ffxx68 0:59717cf94c6a 62 case 's':
ffxx68 0:59717cf94c6a 63 pc.printf ("Sweep...\n");
ffxx68 0:59717cf94c6a 64 // sweep up in frequency by changing the PWM period
ffxx68 0:59717cf94c6a 65 speaker=0.25;
ffxx68 0:59717cf94c6a 66 for (i=0; i<8000; i=i+100) {
ffxx68 0:59717cf94c6a 67 speaker.period(1.0/float(i));
ffxx68 0:59717cf94c6a 68 wait(.02);
ffxx68 0:59717cf94c6a 69 }
ffxx68 0:59717cf94c6a 70 speaker=0.0; // off
ffxx68 0:59717cf94c6a 71 break;
ffxx68 0:59717cf94c6a 72
ffxx68 0:59717cf94c6a 73 case 'p':
ffxx68 0:59717cf94c6a 74 pc.printf ("Police...\n");
ffxx68 0:59717cf94c6a 75 // two tone police siren effect - two periods or two frequencies
ffxx68 0:59717cf94c6a 76 // increase volume - by changing the PWM duty cycle
ffxx68 0:59717cf94c6a 77 for (i=0; i<26; i=i+2) {
ffxx68 0:59717cf94c6a 78 speaker.period(1.0/969.0);
ffxx68 0:59717cf94c6a 79 speaker = float(i)/50.0;
ffxx68 0:59717cf94c6a 80 wait(.5);
ffxx68 0:59717cf94c6a 81 speaker.period(1.0/800.0);
ffxx68 0:59717cf94c6a 82 wait(.5);
ffxx68 0:59717cf94c6a 83 }
ffxx68 0:59717cf94c6a 84 speaker=0.0; // off
ffxx68 0:59717cf94c6a 85 break;
ffxx68 0:59717cf94c6a 86
ffxx68 0:59717cf94c6a 87 case 'h':
ffxx68 0:59717cf94c6a 88 // Play "happy birthday"
ffxx68 0:59717cf94c6a 89 speaker=0.25;
ffxx68 0:59717cf94c6a 90 for (int i=0;i<=24;i++) {
ffxx68 0:59717cf94c6a 91 speaker.period(1.0/notes[i]);
ffxx68 0:59717cf94c6a 92 wait(0.8*intervals[i]/10);
ffxx68 0:59717cf94c6a 93 }
ffxx68 0:59717cf94c6a 94 speaker=0.0; // off
ffxx68 0:59717cf94c6a 95 break;
ffxx68 0:59717cf94c6a 96 }
ffxx68 0:59717cf94c6a 97 }
ffxx68 0:59717cf94c6a 98 pc.printf ("Bye...\n");
ffxx68 0:59717cf94c6a 99 }