main.cpp

00001 /******************************************************************************
00002 ¬   Knightrider.c                                                             ¬
00003 ¬   Uses the onboard LEDS on mBED to continuously perform LED chaser sequence ¬
00004 ¬   LED Chaser sequence timimg can be changed by using the serial comms and   ¬
00005 ¬   activity on digital port.                                                 ¬
00006 ¬                                                                             ¬
00007 ¬   Written by RandomSingh. 05/2010                                           ¬
00008 ¬                                                                             ¬
00009 ******************************************************************************/
00010 
00011 /* Libraries */
00012 #include "mbed.h"
00013 
00014 /* Output Assignements */
00015 DigitalOut myled(LED1);
00016 DigitalOut myled2(LED2);
00017 DigitalOut myled3(LED3);
00018 DigitalOut myled4(LED4);
00019 
00020 /* Input Assignments */
00021 DigitalIn enable(p5);
00022 
00023 /* Interrupt Assignemnts */
00024 InterruptIn event(USBRX);
00025 InterruptIn event2(p16);
00026 
00027 /* Serial Port Assignment */
00028 Serial pc(USBTX, USBRX); // tx, rx
00029 
00030 
00031 /* Macro Definitions */
00032 #define LONGER 0.9
00033 #define LONG 0.4
00034 #define SHORT 0.05
00035 #define FWD 0
00036 #define REV 1
00037 #define SLOW 0
00038 #define MEDIUM 1
00039 #define FAST 2
00040 #define ON 1
00041 #define OFF 0
00042 
00043 /* Prototype Function declartions */
00044 void initialise_LEDS();
00045 void trigger();
00046 void LED_chaser_sequence();
00047 
00048 /* External Variables */
00049 int timer;
00050 short speed;
00051 int direction = FWD;
00052 int phase;
00053 
00054 
00055 
00056 int main() {
00057 
00058     event.rise(&trigger);           // Set up interrupts
00059     event2.rise(&trigger);
00060     initialise_LEDS();
00061     pc.printf("Speed is slow\r\n"); // Default speed is slow
00062     
00063     while(1) 
00064     {// Start of while
00065     
00066         LED_chaser_sequence();
00067     
00068     }// End of while
00069 }// End of main
00070 
00071 
00072 /******************************************************************************
00073 ¬   trigger function - ISR                                                    ¬
00074 ¬   If activity on the rx line of the serial port then this ISR executes      ¬
00075 ¬   This ISR changes the external variable 'speed' value, which is used for   ¬
00076 ¬   timing of the sequence.                                                   ¬
00077 ¬                                                                             ¬
00078 ¬   The objective of this ISR is to change the 'speed' value & transmit a     ¬
00079 ¬   a message to the serial port.                                             ¬                                                                         
00080 ¬                                                                             ¬
00081 ******************************************************************************/
00082 void trigger()
00083 {// Start of trigger
00084         if(speed > FAST)                       // This bit of the code limits value of speed to 2
00085         {// Start of if                        // as there are only three levels of timing 
00086          speed = SLOW;
00087          pc.printf("Speed is slow\r\n");
00088         }// End of if
00089         else
00090         {// Start of else
00091          speed++;
00092         }// End of else
00093     
00094     if(speed == MEDIUM)
00095         pc.printf("Speed is medium\r\n");
00096     
00097     if(speed == FAST)
00098         pc.printf("Speed is fast\r\n");
00099 
00100 }// End of trigger
00101 
00102 void LED_chaser_sequence()
00103 {// Start of LED_chaser_sequence
00104 switch(phase)
00105     {// Start of switch
00106     case 0:  myled = OFF;
00107              myled2 = OFF;
00108              myled3 = OFF;
00109              myled4 = OFF;
00110              wait(LONG);
00111              wait(SHORT);
00112              direction = FWD;
00113              phase++;
00114              break;
00115     case 1:  myled = ON;
00116              myled2 = OFF;
00117              myled3 = OFF;
00118              myled4 = OFF;
00119              wait(SHORT);
00120              if(direction == FWD)
00121              {// Start of if
00122                 phase++;
00123              }// End of if
00124              else
00125              {// Start of else
00126                 phase--;
00127              }// End of else
00128              break;
00129     case 2:  myled = OFF;
00130              myled2 = ON;
00131              myled3 = OFF;
00132              myled4 = OFF;
00133              wait(SHORT);
00134                 if(direction == FWD)
00135              {// Start of if
00136                 phase++;
00137              }// End of if
00138              else
00139              {// Start of else
00140                 phase--;
00141              }// End of else
00142              break;
00143     case 3:  myled = OFF;
00144              myled2 = OFF;
00145              myled3 = ON;
00146              myled4 = OFF;
00147              wait(SHORT);
00148                 if(direction == FWD)
00149              {// Start of if
00150                 phase++;
00151              }// End of if
00152              else
00153              {// Start of else
00154                 phase--;
00155              }// End of else
00156              break;
00157    case  4:  myled = OFF;
00158              myled2 = OFF;
00159              myled3 = OFF;
00160              myled4 = ON;
00161              wait(SHORT);
00162              direction = REV;
00163              phase--;
00164              break;
00165    default : 
00166             wait(SHORT);
00167             break;
00168             
00169     }// End of switch
00170     
00171     switch(speed)
00172     {// Start of switch
00173         case SLOW   : wait(LONGER);
00174                       break;
00175         case MEDIUM : wait(LONG);
00176                       break;
00177         case FAST   : wait(SHORT);
00178                       break;
00179         default     :
00180                       wait(SHORT);
00181                       break;
00182     }// End of switch
00183 
00184 }// End of LED_chaser_sequence
00185 
00186 void initialise_LEDS()
00187 {// Start of initialise_LEDS
00188 
00189     myled = OFF;
00190     myled2 = OFF;
00191     myled3 = OFF;
00192     myled4 = OFF;
00193 
00194 }// End of initialise_LEDS