blink.cpp

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