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  • Author Author: oksbwn
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Arduino | Tutorial 3 | Serial Communication

oksbwn

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  • Are you sure that the code

     

    if (Serial) {
  // communicate
}

     

    makes sense in the video? Isn't Serial always different from 0, because it's a static object that has a non-zero address? even if Serial.begin(9600) fails?

  • Former Member
    Former Member in reply to Jan Cumps

      Apparently, a reference to Serial in an if or while argument context evaluates to true if the specified serial port is available else there is a permanent/temporary error.  There must be something hidden in the compilation/interpreter that treats Serial special.  An if( Serial.isConnected() ) would be better.  Secrets are bad engineering practices but what can you do?  I cannot find any documentation of the static Serial object other than what's in the arduino.cc API.  Have you?

     

    To guard against a single spurious failure instance, I use this in setup() instead of the if-statement for Serial applications:

     

    int count_down = 3; 
    while( ! Serial ) {
          // Sleep 1 second if not yet ready.
          delay( 1000 );
          // Tried the maximum allowed times already?
          if( count_down-- < 1 ) {
               // Tried 3 seconds to get the serial connection ready - giving up.
               // Timeout error processing goes here
          }
    }
  • in reply to Former Member

    The compiler is a standard c++ compiler and the linker is also a known one. So whatever the Serial library does must be a c++ construct.

     

    The source for the System class is open, so we can have a look ourselves. Let's do that.

    The first who finds it is king for a day...

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