blinker.cpp

00001 // blinker.cpp - send a morse pattern to LED1
00002 //
00003 // Function morse() is one way for running LED1 with a blinking sequence using
00004 // a busy wait, until the sequence is completed.
00005 //
00006 //    Blinker b;
00007 //    b.morse(" x xxx x    ");      send one time morse sequence, interval = 0.2
00008 //    b.morse(" x xxx x    ",0.5);  send one time morse sequence, interval = 0.5
00009 //
00010 // Function morse(o) got the additional feature to stop an ongoing timer based
00011 // blinking sequence.
00012 //    
00013 // The alternative is to setup an ever repeating blink sequence via LED1 using
00014 // function blink(), which is non waiting.
00015 //
00016 //    Blinker b;
00017 //    b.blink(" x xxx x    ");         repeating blink sequence, interval = 0.2
00018 //    b.blink(" x xxx x    ",0.5);     repeating blink sequence, interval = 0.5
00019 //    b.blink();                       stops blinking sequence
00020 //
00021 
00022 #include "bricks/target.h"
00023 #include "bricks/blinker.h"
00024 
00025 #ifndef LED_INVERTED
00026 #   define LED_ON  1
00027 #   define LED_OFF 0
00028 #else
00029 #   define LED_ON  0
00030 #   define LED_OFF 1
00031 #endif
00032 
00033 #ifndef BLINK_LED
00034 #   define BLINK_LED LED1
00035 #endif
00036 
00037    static DigitalOut led(BLINK_LED);    // being used for morse sequence
00038    static Ticker ticker;                // triggers periodic callbacks
00039    static const char *pointer = 0;      // 0 means morse activity disabled
00040    static const char *sequence = 0;     // next morse sequence for repeats
00041 
00042    void Blinker::stop()
00043    {
00044       pointer = 0;
00045       sequence = 0;
00046    }
00047 
00048    void Blinker::setled(bool state)
00049    {
00050       led = (state ? LED_ON : LED_OFF);
00051    }
00052 
00053    void Blinker::morse(const char *pattern, double interval)
00054    {
00055        stop();                          // stop current sequence
00056        
00057        for (; *pattern; pattern++)
00058        {
00059           setled(*pattern != ' ');
00060           wait(interval);               // busy waiting for interval time
00061        }
00062    }
00063           
00064 // callback for LED1 ticker controlled blinking   
00065            
00066    static void cbBlinker(void)         // blinker callback
00067    {
00068       if (pointer != 0)
00069       {
00070          if (*pointer == 0)
00071          {
00072             pointer = sequence;        // reset pointer to followup sequence
00073          }
00074         
00075          if (*pointer)
00076          {
00077             led = (*pointer++ == ' ') ? LED_OFF : LED_ON;
00078          }
00079       }
00080    }
00081    
00082    void Blinker::blink(const char *pattern, const char* next, double interval) 
00083    {
00084       pointer = 0;                      // stop current activities
00085       led = LED_OFF;                    // reset led with LED_OFF
00086       
00087       sequence = next;                  // init morse sequence   
00088          
00089       ticker.attach(cbBlinker,interval);// next LED state after every interval
00090       pointer = pattern;                // enable callback activty
00091    }  
00092 
00093    void Blinker::blink(const char *pattern, double interval)
00094    {
00095        blink(pattern,pattern,interval);
00096    }
00097    
00098