Richard Kuo / Mbed OS NTOUEE-mbed-PWM_siren

mbed PWM output to play siren

main.cpp@0:ed48c1d4c02f, 2016-10-21 (annotated)

Committer:
rkuo2000
Date:
Fri Oct 21 07:35:16 2016 +0000
Revision:
0:ed48c1d4c02f
mbed PWM siren

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rkuo2000 0:ed48c1d4c02f 1 //NuMaker-PFM-NUC472 PWM0 output Siren to a speaker
rkuo2000 0:ed48c1d4c02f 2 #include "mbed.h"
rkuo2000 0:ed48c1d4c02f 3
rkuo2000 0:ed48c1d4c02f 4 #define Ambulance_Siren_Low 650
rkuo2000 0:ed48c1d4c02f 5 #define Ambulance_Siren_High 900
rkuo2000 0:ed48c1d4c02f 6 #define Ambulance_Siren_L_period 400 // 0.4 sec
rkuo2000 0:ed48c1d4c02f 7 #define Ambulance_Siren_H_period 600 // 0.6 sec
rkuo2000 0:ed48c1d4c02f 8
rkuo2000 0:ed48c1d4c02f 9 #define PoliceCar_Siren_Low 650
rkuo2000 0:ed48c1d4c02f 10 #define PoliceCar_Siren_High 1450
rkuo2000 0:ed48c1d4c02f 11 #define PoliceCar_Siren_L_duration 230 // 0.23 sec
rkuo2000 0:ed48c1d4c02f 12 #define PoliceCar_Siren_H_duration 100 // 0.1 sec
rkuo2000 0:ed48c1d4c02f 13
rkuo2000 0:ed48c1d4c02f 14 PwmOut pwm0(PF_9); // PWM0 pin
rkuo2000 0:ed48c1d4c02f 15
rkuo2000 0:ed48c1d4c02f 16 void Ambulance_Siren(uint32_t siren_no)
rkuo2000 0:ed48c1d4c02f 17 {
rkuo2000 0:ed48c1d4c02f 18 int i;
rkuo2000 0:ed48c1d4c02f 19 for (i=0; i<siren_no; i++) {
rkuo2000 0:ed48c1d4c02f 20 pwm0.period_us(1000000/Ambulance_Siren_Low);
rkuo2000 0:ed48c1d4c02f 21 pwm0.pulsewidth_us(1000000/Ambulance_Siren_Low/2); // set duty cycle to 50%
rkuo2000 0:ed48c1d4c02f 22 Thread::wait(Ambulance_Siren_L_period);
rkuo2000 0:ed48c1d4c02f 23 pwm0.period_us(1000000/Ambulance_Siren_High);
rkuo2000 0:ed48c1d4c02f 24 pwm0.pulsewidth_us(1000000/Ambulance_Siren_High/2); // set duty cycle to 50%
rkuo2000 0:ed48c1d4c02f 25 Thread::wait(Ambulance_Siren_H_period);
rkuo2000 0:ed48c1d4c02f 26 }
rkuo2000 0:ed48c1d4c02f 27 pwm0.pulsewidth_us(0);
rkuo2000 0:ed48c1d4c02f 28 }
rkuo2000 0:ed48c1d4c02f 29
rkuo2000 0:ed48c1d4c02f 30 void PoliceCar_Siren(uint32_t siren_no)
rkuo2000 0:ed48c1d4c02f 31 {
rkuo2000 0:ed48c1d4c02f 32 int i, j;
rkuo2000 0:ed48c1d4c02f 33 int siren_freq;
rkuo2000 0:ed48c1d4c02f 34
rkuo2000 0:ed48c1d4c02f 35 for (i=0; i<siren_no; i++) {
rkuo2000 0:ed48c1d4c02f 36 siren_freq = PoliceCar_Siren_Low;
rkuo2000 0:ed48c1d4c02f 37 for (j=0; j<(PoliceCar_Siren_L_duration); j++) {
rkuo2000 0:ed48c1d4c02f 38 pwm0.period_us(1000000/siren_freq);
rkuo2000 0:ed48c1d4c02f 39 pwm0.pulsewidth_us(1000000/siren_freq/2); // set duty cycle to 50%
rkuo2000 0:ed48c1d4c02f 40 Thread::wait(1);
rkuo2000 0:ed48c1d4c02f 41 siren_freq = siren_freq + (PoliceCar_Siren_High - PoliceCar_Siren_Low)/230;
rkuo2000 0:ed48c1d4c02f 42 }
rkuo2000 0:ed48c1d4c02f 43 siren_freq = PoliceCar_Siren_High;
rkuo2000 0:ed48c1d4c02f 44 for (j=0; j<PoliceCar_Siren_L_duration; j++) {
rkuo2000 0:ed48c1d4c02f 45 pwm0.period_us(1000000/siren_freq);
rkuo2000 0:ed48c1d4c02f 46 pwm0.pulsewidth_us(1000000/siren_freq/2); // set duty cycle to 50%
rkuo2000 0:ed48c1d4c02f 47 Thread::wait(1);
rkuo2000 0:ed48c1d4c02f 48 siren_freq = siren_freq - (PoliceCar_Siren_High - PoliceCar_Siren_Low)/100;
rkuo2000 0:ed48c1d4c02f 49 }
rkuo2000 0:ed48c1d4c02f 50 }
rkuo2000 0:ed48c1d4c02f 51 pwm0.pulsewidth_us(0);
rkuo2000 0:ed48c1d4c02f 52 }
rkuo2000 0:ed48c1d4c02f 53
rkuo2000 0:ed48c1d4c02f 54 int main()
rkuo2000 0:ed48c1d4c02f 55 {
rkuo2000 0:ed48c1d4c02f 56 while(1) {
rkuo2000 0:ed48c1d4c02f 57 Ambulance_Siren(5);
rkuo2000 0:ed48c1d4c02f 58 PoliceCar_Siren(5);
rkuo2000 0:ed48c1d4c02f 59 }
rkuo2000 0:ed48c1d4c02f 60 }