Diff: main.cpp

Revision:

0:5cef91b1b767

diff -r 000000000000 -r 5cef91b1b767 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Aug 14 17:47:40 2014 +0000
@@ -0,0 +1,38 @@
+//****************************************
+//  ES305 Linear Control Systems
+//  Lab 2 - Introduction to mbed microcontroller
+//  Exercise 4 - Pulse Width Modulation
+//  Adjusts Pulse Width Modulation output to vary the brightness of an onboard LED.
+//  Uses the keyboard to increase or decrease the the PWM
+//
+//  Brian Connett, LCDR, USN
+//  exercise and code derived from mbed.org
+//****************************************
+
+#include "mbed.h"                           //mbed header file from mbed.org includes MOST APIs required to operate LPC
+
+Serial pc(USBTX, USBRX);                    //Create a Serial port connected to USB
+PwmOut pwm1(LED1);                          //Creates a pulse-width modulation digital output assigned to the variable pwm1 at LED 1
+float duty_cycle=0.0;
+
+int main()
+{
+    pc.baud(921600);                         //Set up serial port baud rate
+    pc.printf("Control of LED dimmer by host terminal\n\r");
+    pc.printf("Press 'u' = to increase duty cycle, 'd' to decrease duty cycle\n\r");
+    while(1) {
+        char c =pc.getc();                  //Using the getc public member function of SERIAL to retrieve key press
+        wait(0.001);
+        if ((c == 'u') && (duty_cycle < 1.0)) { //When 'u' key is pressed duty cycle increases up to 100%
+            duty_cycle += 0.01;
+            pwm1 = duty_cycle;
+        }
+        if((c=='d')&&(duty_cycle > 0.0)) { //When 'd' key is pressed duty cycle increases down to 0%
+            duty_cycle -= 0.01;
+            pwm1 = duty_cycle;
+        }
+        pc.printf("%c %1.3f \n \r",c,duty_cycle);
+    }
+
+
+}
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