Byte Digital Output

Projects Programming
1

Hi,

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

THE CODE

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()
{
delay(200);

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));

delay(200);

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

}

2

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:

   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));
3

I tryed that, but still doesn´t works.

It blinks 30, 33, and 36.

4 
byte b = 00000111;

This sets b to the octal value 0111 which is the bit pattern 01001001. What I think you wanted was:

byte b = B00000111;

Pete

5

Perfect,

Thank you so much

6

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()
{
delay(200);

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));

delay(200);

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);

}