File content as of revision 0:a06d2b459821:

/**************************************************************
/ ME21001 Group m-nn
/
/ Lab 04 Exercise 4
/
/ This program reads an analogue input and displays the results
/ to the PC
/
*/
#include "mbed.h"
Serial pc(USBTX, USBRX);    // USB serial interface

AnalogIn A_in(p17);         // analogue input pin for reference values
PwmOut led1(LED1);
PwmOut led2(LED2);
PwmOut led3(LED3);
PwmOut led4(LED4);
int main() {
    
float analogue_val=0.0;     // variable to hold the analogue input 
                            // values as decimals
                            // set the USB serial interface baud rate
led1.period(0.020);
led2.period(0.020);
led3.period(0.020);
led4.period(0.020);


    while(1) {              // repeat indefinitely

                            // read the voltage on the analogue input pin and 
                            // convert it to a
                            // decimal number with 12-bit resolution

analogue_val = A_in.read(); // export the readings to a terminal program 
                            // via the USB cable
if( analogue_val<0.25){
    led1=(analogue_val/0.25);
    led2=led3=led4=0;
    }
    else if (analogue_val<0.5){
        led1=1;
        led2=((analogue_val-0.25)/0.25);
        led3=led4=0;
        }
        else if (analogue_val<0.75){
            led1=led2=1;
            led3=((analogue_val-0.5)/0.25);
            led4=0;
            }
            else{
                led1=led2=led3=1;
                led4=((analogue_val-0.75)/0.25);
                }
                wait(0.l);
                }
          }