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Topic: Byte Digital Output (Read 1 time) previous topic - next topic



I need to put a Byte in an 8 bits port; I made the follow code but it´s not working as it should for example in pins 30, 31 and 32 I should have a High output (Blinking), but I have high only in 30 and 31.

Please, could somebody help me?
I´m using the Arduino mega 2560


byte b = 00000111;

void setup()
  pinMode(30, OUTPUT);
  pinMode(31, OUTPUT);
  pinMode(32, OUTPUT);
  pinMode(33, OUTPUT);
  pinMode(34, OUTPUT);
  pinMode(35, OUTPUT);
  pinMode(36, OUTPUT);
  pinMode(37, OUTPUT);

void loop()

   digitalWrite(30, bitRead (b, 1));
   digitalWrite(31, bitRead (b, 2));
   digitalWrite(32, bitRead (b, 3));
   digitalWrite(33, bitRead (b, 4));
   digitalWrite(34, bitRead (b, 5));
   digitalWrite(35, bitRead (b, 6));
   digitalWrite(36, bitRead (b, 7));
   digitalWrite(37, bitRead (b, 8));

   digitalWrite(30, LOW);
   digitalWrite(31, LOW);
   digitalWrite(32, LOW);
   digitalWrite(33, LOW);
   digitalWrite(34, LOW);
   digitalWrite(35, LOW);
   digitalWrite(36, LOW);
   digitalWrite(37, LOW);


The parameter for which bit to read starts at 0 for the least-significant bit, so you have simply shifted everything one bit. The correct code would be:

Code: [Select]
   digitalWrite(30, bitRead (b, 0));
   digitalWrite(31, bitRead (b, 1));
   digitalWrite(32, bitRead (b, 2));
   digitalWrite(33, bitRead (b, 3));
   digitalWrite(34, bitRead (b, 4));
   digitalWrite(35, bitRead (b, 5));
   digitalWrite(36, bitRead (b, 6));
   digitalWrite(37, bitRead (b, 7));


I tryed that, but still doesn´t works.

It blinks 30, 33, and 36.


Code: [Select]
byte b = 00000111;
This sets b to the octal value 0111 which is the bit pattern 01001001. What I think you wanted was:
Code: [Select]
byte b = B00000111;

Don't send me technical questions via Private Message.



Thank you so much


Hi, again.

I´m trying to change the code in order to manipulate ports, I put the following line codes, and comment the code that was working well, and now it doesn´t make anything.

void setup()
   DDRD = B11111111;
// pinMode(0, OUTPUT);
// pinMode(1, OUTPUT);
// pinMode(2, OUTPUT);
  //pinMode(3, OUTPUT);
  //pinMode(4, OUTPUT);
// pinMode(5, OUTPUT);
// pinMode(6, OUTPUT);
  //pinMode(7, OUTPUT);

void loop()
   PORTD = B10011100;

  // digitalWrite(0, bitRead (salida, 0));
  // digitalWrite(1, bitRead (salida, 1));
  // digitalWrite(2, bitRead (salida, 2));
  // digitalWrite(3, bitRead (salida, 3));
  // digitalWrite(4, bitRead (salida, 4));
  // digitalWrite(5, bitRead (salida, 5));
  // digitalWrite(6, bitRead (salida, 6));
  // digitalWrite(7, bitRead (salida, 7));

   PORTD = 0;
  // digitalWrite(0, LOW);
  // digitalWrite(1, LOW);
  // digitalWrite(2, LOW);
  // digitalWrite(3, LOW);
  // digitalWrite(4, LOW);
  // digitalWrite(5, LOW);
  // digitalWrite(6, LOW);
  // digitalWrite(7, LOW);

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