costos:
I try to place DDRA in a programm but when I compile, the message "DDRA was not declared in this scope".
Why do you want to?
Where do you see DDRA in the datasheet? Give the page number please.
This compiles:
void setup ()
{
DDRB = 0;
}
void loop () {}
Result:
Binary sketch size: 468 bytes (of a 32256 byte maximum)