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    static DigitalOut led(LED1);         // LED1, being used for morse sequence
00034    static Ticker ticker;                // triggers periodic callbacks
00035    static const char *pointer = 0;      // 0 means morse activity disabled
00036    static const char *sequence = 0;     // next morse sequence for repeats
00037 
00038    void Blinker::morse(const char *pattern, double interval)
00039    {
00040        pointer = 0;                     // disable ticker based blinking
00041        sequence = 0;                    // set also empty sequence
00042        
00043        for (; *pattern; pattern++)
00044        {
00045           led = (*pattern == ' ') ? LED_OFF : LED_ON;
00046           wait(interval);               // busy waiting for interval time
00047        }
00048    }
00049           
00050 // callback for LED1 ticker controlled blinking   
00051            
00052    static void cbBlinker(void)         // blinker callback
00053    {
00054        if (pointer != 0)
00055       {
00056          if (*pointer == 0)
00057          {
00058             pointer = sequence;        // reset pointer to followup sequence
00059          }
00060         
00061          if (*pointer)
00062          {
00063             led = (*pointer++ == ' ') ? LED_OFF : LED_ON;
00064          }
00065       }
00066    }
00067    
00068    void Blinker::blink(const char *pattern, const char* next, double interval) 
00069    {
00070       pointer = 0;                      // stop current activities
00071       led = LED_OFF;                    // reset led with LED_OFF
00072       
00073       sequence = next;                  // init morse sequence   
00074          
00075       ticker.attach(cbBlinker,interval);// next LED state after every interval
00076       pointer = pattern;                // enable callback activty
00077    }  
00078 
00079    void Blinker::blink(const char *pattern, double interval)
00080    {
00081        blink(pattern,pattern,interval);
00082    }
00083    
00084