main.cpp

00001 /*********************************************************************
00002   led_fsm      first mbed (lpc1768) program
00003                Simple finite state machine for 
00004                mbed's onboard LEDs sequencing
00005 
00006  author: Ivan Vengust 'vitrzin'
00007  last change: 14. oct. 2010               
00008 *********************************************************************/
00009 #include "mbed.h"
00010 
00011 // Function prototypes
00012 int fsm(void);
00013 int fsm1(void);
00014 
00015 // Global variables
00016 DigitalOut led1(LED1);
00017 DigitalOut led2(LED2);
00018 DigitalOut led3(LED3);
00019 DigitalOut led4(LED4);
00020 
00021 // main ************************************************************
00022 int main() 
00023 {
00024     int c(0), status;
00025     
00026     while(1) 
00027     {
00028         if (c > 2) // decide which sequence
00029             status = fsm1(); // call sequence change
00030         else
00031             status = fsm();
00032         
00033         if (status == 0)
00034         {
00035             c = ++c % 5; // count finished sequences
00036         }
00037     }
00038 }
00039 
00040 /**********************************************************************
00041   fsm()   Simple finite state machine
00042            Each call to 'fsm' will advance state machine to next state
00043           return value: current state 
00044 **********************************************************************/  
00045 int fsm(void) // light each led on turn - 4 states
00046 {
00047     static int st(0); // sequence state
00048     const int dly(200); // base delay - 200 ms
00049 
00050     switch(st)
00051     {
00052        case 0:            //  state 0
00053          led4 = 0; // change leds 
00054          led3 = 0;
00055          led2 = 0;
00056          led1 = 1;
00057          wait_ms(dly*3); // wait longer in initial state
00058          ++st;     // switch to next state       
00059          break;
00060        case 1:            //  state 1 
00061          led1 = 0;
00062          led2 = 1;
00063          ++st;
00064          break;
00065        case 2:            //  state 2
00066          led2 = 0;
00067          led3 = 1;
00068          ++st;
00069          break;
00070        case 3:            //  state 3
00071          led3 = 0;
00072          led4 = 1;
00073          st=0;    // switch to initial state       
00074          break;
00075     }
00076     wait_ms(dly);
00077     return st;
00078 }
00079 
00080 int fsm1(void) // light led column - 8 states
00081 {
00082     static int st(0); // sequence state
00083     const int dly(400); // base delay - 200 ms
00084 
00085     switch(st)
00086     {
00087        case 0:            //  state 0
00088          led4 = 0; // change leds 
00089          led3 = 0;
00090          led2 = 0;
00091          led1 = 0;
00092          wait_ms(dly*2); // wait longer in initial state
00093          ++st;     // switch to next state       
00094          break;
00095        case 1:            //  state 1 
00096          led4 = 1;
00097          ++st;
00098          break;
00099        case 2:            //  state 2
00100          led3 = 1;
00101          ++st;
00102          break;
00103        case 3:            //  state 3
00104          led2 = 1;
00105          ++st;
00106          break;
00107        case 4:            //  state 4
00108          led1 = 1;
00109          ++st;
00110          break;
00111        case 5:            //  state 5
00112          led1 = 0;
00113          ++st;
00114          break;
00115        case 6:            //  state 6
00116          led2 = 0;
00117          ++st;
00118          break;
00119        case 7:            //  state 7
00120          led3 = 0;
00121          ++st;
00122          break;
00123        case 8:            //  state 8
00124          led4 = 0;
00125          st=0;    // switch to initial state       
00126          break;
00127     }
00128     wait_ms(dly);
00129     return st;
00130 }