beginner: Port set

Hi Aladin

A little tutorial.

Your initial question was about toggling individual pins, but the second example solution provided by Andrej toggled all 8 bits at the same time. In this case it is the most elegant and fastest solution, but doesn't work if, say, you were only using 6 of the 8 port pins, because you would reset the other 2 pins that might be used for something else.

AVRCo Pascal a very rich and powerful language and there are solutions to most problems. Here is a solution based on your original code that will work on a smaller number of pins.

Code

DDRD := 255;
for x:=0 to 7 do
  incl( PortD,x ); // or, more slowly SetBit( PortD, x, 1 );
  MDelay(100);
  //Incl( DDRD,x );
  excl( PortD, x); // or more slowly (SetBit( PortD, x, 0 );
  MDelay(100);
endfor;

Some other things that might interest you - it is possible to give your port pins names, and so make your code more readble. Also, as well as using 1 and 0 you can treat them as boolean and use TRUE and FALSE. So, for example, you could do this

Code

var
  LED1 [@PortD, 0 ] : bit;

begin

  incl( DDRD, 0);

  LED1 := TRUE;
  loop
    mdelay(100);
    LED1 := not LED1; // blink
  end_loop;
end;

Enjoy!

Merlin.

beginner: Port set

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