USNA ES305 / Mbed 2 deprecated es305_lab2_ex4

ES305 Lab2 Exercise 4 Adjusts Pulse Width Modulation output to vary the brightness of an onboard LED. Uses the keyboard to increase or decrease the the PWM

Dependencies:   mbed

main.cpp@0:5cef91b1b767, 2014-08-14 (annotated)

Committer:
brianconnett
Date:
Thu Aug 14 17:47:40 2014 +0000
Revision:
0:5cef91b1b767
ES305 Lab2 Exercise 4; Adjusts Pulse Width Modulation output to vary the brightness of an onboard LED. Uses the keyboard to increase or decrease the the PWM

Who changed what in which revision?

UserRevisionLine numberNew contents of line
brianconnett 0:5cef91b1b767 1 //****************************************
brianconnett 0:5cef91b1b767 2 // ES305 Linear Control Systems
brianconnett 0:5cef91b1b767 3 // Lab 2 - Introduction to mbed microcontroller
brianconnett 0:5cef91b1b767 4 // Exercise 4 - Pulse Width Modulation
brianconnett 0:5cef91b1b767 5 // Adjusts Pulse Width Modulation output to vary the brightness of an onboard LED.
brianconnett 0:5cef91b1b767 6 // Uses the keyboard to increase or decrease the the PWM
brianconnett 0:5cef91b1b767 7 //
brianconnett 0:5cef91b1b767 8 // Brian Connett, LCDR, USN
brianconnett 0:5cef91b1b767 9 // exercise and code derived from mbed.org
brianconnett 0:5cef91b1b767 10 //****************************************
brianconnett 0:5cef91b1b767 11
brianconnett 0:5cef91b1b767 12 #include "mbed.h" //mbed header file from mbed.org includes MOST APIs required to operate LPC
brianconnett 0:5cef91b1b767 13
brianconnett 0:5cef91b1b767 14 Serial pc(USBTX, USBRX); //Create a Serial port connected to USB
brianconnett 0:5cef91b1b767 15 PwmOut pwm1(LED1); //Creates a pulse-width modulation digital output assigned to the variable pwm1 at LED 1
brianconnett 0:5cef91b1b767 16 float duty_cycle=0.0;
brianconnett 0:5cef91b1b767 17
brianconnett 0:5cef91b1b767 18 int main()
brianconnett 0:5cef91b1b767 19 {
brianconnett 0:5cef91b1b767 20 pc.baud(921600); //Set up serial port baud rate
brianconnett 0:5cef91b1b767 21 pc.printf("Control of LED dimmer by host terminal\n\r");
brianconnett 0:5cef91b1b767 22 pc.printf("Press 'u' = to increase duty cycle, 'd' to decrease duty cycle\n\r");
brianconnett 0:5cef91b1b767 23 while(1) {
brianconnett 0:5cef91b1b767 24 char c =pc.getc(); //Using the getc public member function of SERIAL to retrieve key press
brianconnett 0:5cef91b1b767 25 wait(0.001);
brianconnett 0:5cef91b1b767 26 if ((c == 'u') && (duty_cycle < 1.0)) { //When 'u' key is pressed duty cycle increases up to 100%
brianconnett 0:5cef91b1b767 27 duty_cycle += 0.01;
brianconnett 0:5cef91b1b767 28 pwm1 = duty_cycle;
brianconnett 0:5cef91b1b767 29 }
brianconnett 0:5cef91b1b767 30 if((c=='d')&&(duty_cycle > 0.0)) { //When 'd' key is pressed duty cycle increases down to 0%
brianconnett 0:5cef91b1b767 31 duty_cycle -= 0.01;
brianconnett 0:5cef91b1b767 32 pwm1 = duty_cycle;
brianconnett 0:5cef91b1b767 33 }
brianconnett 0:5cef91b1b767 34 pc.printf("%c %1.3f \n \r",c,duty_cycle);
brianconnett 0:5cef91b1b767 35 }
brianconnett 0:5cef91b1b767 36
brianconnett 0:5cef91b1b767 37
brianconnett 0:5cef91b1b767 38 }