Luis Silvio Cordova Rivadeneira / Mbed 2 deprecated UPSM_PWM

Ejemplos varios de PWM

Dependencies:   mbed

main.cpp@0:b3c72630f04c, 2020-02-07 (annotated)

Committer:
lscordovar
Date:
Fri Feb 07 20:18:51 2020 +0000
Revision:
0:b3c72630f04c
Ejemplos de PWM

Who changed what in which revision?

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lscordovar 0:b3c72630f04c 1 /*
lscordovar 0:b3c72630f04c 2 Exercise : Create a PWM signal which we can see on an
lscordovar 0:b3c72630f04c 3 oscilloscope. The following code will generate a 100 Hz
lscordovar 0:b3c72630f04c 4 pulse with 50% duty cycle
lscordovar 0:b3c72630f04c 5 */
lscordovar 0:b3c72630f04c 6
lscordovar 0:b3c72630f04c 7
lscordovar 0:b3c72630f04c 8 #include "mbed.h"
lscordovar 0:b3c72630f04c 9 PwmOut PWM1(p21);
lscordovar 0:b3c72630f04c 10 int main()
lscordovar 0:b3c72630f04c 11 {
lscordovar 0:b3c72630f04c 12 PWM1.period(0.010); // set PWM period to 10 ms
lscordovar 0:b3c72630f04c 13 PWM1=0.5; // set duty cycle to 50%
lscordovar 0:b3c72630f04c 14 }
lscordovar 0:b3c72630f04c 15
lscordovar 0:b3c72630f04c 16 /*
lscordovar 0:b3c72630f04c 17 Exercise : This example code uses a pulse width
lscordovar 0:b3c72630f04c 18 modulation signal to increase and decrease
lscordovar 0:b3c72630f04c 19 the brightness of the onboard LED
lscordovar 0:b3c72630f04c 20 The program requires the use of a host terminal
lscordovar 0:b3c72630f04c 21 application to communicate the
lscordovar 0:b3c72630f04c 22 brightness value to the mbed, in this example by
lscordovar 0:b3c72630f04c 23 using the ‘u’ and ‘d’ keys
lscordovar 0:b3c72630f04c 24 */
lscordovar 0:b3c72630f04c 25
lscordovar 0:b3c72630f04c 26
lscordovar 0:b3c72630f04c 27
lscordovar 0:b3c72630f04c 28 // host terminal LED dimmer control
lscordovar 0:b3c72630f04c 29 #include "mbed.h"
lscordovar 0:b3c72630f04c 30 Serial pc(USBTX, USBRX); // tx, rx
lscordovar 0:b3c72630f04c 31 PwmOut led(LED1);
lscordovar 0:b3c72630f04c 32 float brightness=0.0;
lscordovar 0:b3c72630f04c 33 int main()
lscordovar 0:b3c72630f04c 34 {
lscordovar 0:b3c72630f04c 35 pc.printf(“Control of LED dimmer by host terminal\n\r");
lscordovar 0:b3c72630f04c 36 pc.printf("Press 'u‘ = brighter, 'd‘ = dimmer\n\r");
lscordovar 0:b3c72630f04c 37 while(1) {
lscordovar 0:b3c72630f04c 38 char c = pc.getc();
lscordovar 0:b3c72630f04c 39 wait(0.001);
lscordovar 0:b3c72630f04c 40 if((c == 'u') && (brightness < 0.1)) {
lscordovar 0:b3c72630f04c 41 brightness += 0.001;
lscordovar 0:b3c72630f04c 42 led = brightness;
lscordovar 0:b3c72630f04c 43 }
lscordovar 0:b3c72630f04c 44 if((c == 'd') && (brightness > 0.0)) {
lscordovar 0:b3c72630f04c 45 brightness -= 0.001;
lscordovar 0:b3c72630f04c 46 led = brightness;
lscordovar 0:b3c72630f04c 47 }
lscordovar 0:b3c72630f04c 48 pc.printf("%c %1.3f \n \r",c,brightness);
lscordovar 0:b3c72630f04c 49 }
lscordovar 0:b3c72630f04c 50 }
lscordovar 0:b3c72630f04c 51
lscordovar 0:b3c72630f04c 52 /*
lscordovar 0:b3c72630f04c 53
lscordovar 0:b3c72630f04c 54 Exercise 7: We are going to use the PWM to play the start of an
lscordovar 0:b3c72630f04c 55 old English folk tune ‘Oranges and Lemons’. If you’re a reader of
lscordovar 0:b3c72630f04c 56 music you will recognise this in the Figure below
lscordovar 0:b3c72630f04c 57 • You just need to know that any note which is a minim lasts twice
lscordovar 0:b3c72630f04c 58 as long as a crotchet, which in turn lasts twice as long as a quaver
lscordovar 0:b3c72630f04c 59
lscordovar 0:b3c72630f04c 60 The following program implements the ‘Oranges and Lemons‘ musical
lscordovar 0:b3c72630f04c 61 output
lscordovar 0:b3c72630f04c 62 */
lscordovar 0:b3c72630f04c 63
lscordovar 0:b3c72630f04c 64 // Oranges and Lemons program
lscordovar 0:b3c72630f04c 65 #include "mbed.h"
lscordovar 0:b3c72630f04c 66 PwmOut buzzer(p21);
lscordovar 0:b3c72630f04c 67 float frequency[]= {659,554,659,554,550,494,554,587,494,659,554,440};
lscordovar 0:b3c72630f04c 68 //frequency array
lscordovar 0:b3c72630f04c 69 float beat[]= {1,1,1,1,1,0.5,0.5,1,1,1,1,2};
lscordovar 0:b3c72630f04c 70 //beat array
lscordovar 0:b3c72630f04c 71 int main()
lscordovar 0:b3c72630f04c 72 {
lscordovar 0:b3c72630f04c 73 while (1) {
lscordovar 0:b3c72630f04c 74 for (int i=0; i<=11; i++) {
lscordovar 0:b3c72630f04c 75 buzzer.period(1/(frequency[i])); // set PWM period
lscordovar 0:b3c72630f04c 76 buzzer=0.5; // set duty cycle
lscordovar 0:b3c72630f04c 77 wait(0.5*beat[i]); // hold for beat period
lscordovar 0:b3c72630f04c 78 }
lscordovar 0:b3c72630f04c 79 }
lscordovar 0:b3c72630f04c 80 }
lscordovar 0:b3c72630f04c 81