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Serial Monitor - code that compares the incoming byte data to characters 1 and 0

Hi

I am a beginner to the arduino. To cut a long story short I have the code Serial.read which appears to read the 8 bit ascii value of a character.. This value is read into an int variable called Byte Received

Later in the code there is this

    if(ByteReceived == '1') // Single Quote! This is a character.
    {
      digitalWrite(led,HIGH);
      Serial.print(" LED ON ");
    }
    
    if(ByteReceived == '0')
    {
      digitalWrite(led,LOW);
      Serial.print(" LED OFF");
    }

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I do not understand the if statements e,g,

if(ByteReceived == '1')

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ByteReceived is an int and a value of 0 is null and a value of 1 is start of heading. Why are we comparing to 0 and 1 and why is it a character comparison ?

Furthermore I never get LED ON or LED OFF displayed but an led which is not pin 13 does flash .

Any help is much appreciated

Thanks

Fabrice Lambert

if(ByteReceived == '1')

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Here, you compare ByteReceived with the character '1'.
And if you refer to an ASCII table, that character's numeric value is 49.
Same goes for the character '0', it's numeric value is 48 (and not 0, neither NULL).

See this article on wikipedia.

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sarabande

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Andrea Edwards

ASKER

Thanks for explaning that the smaller operand is expanded to the same as the larger operand. I didnt see how that comparison could be possible. I have another problem with the code but I will ask another question on that

Andrea Edwards

ASKER

thank you