How to compile AVR code in Arduino?

Question

Why does the following code not work in Arduino?

#include<avr/io.h>
void setup()
{
    DDRA = 0xFF;
}
void loop()
{
    PORTA = 0xAA;
    _delay_ms(1000);
    PORTA = 0x55;
    _delay_ms(1000);
}

I get the following error. "DDRA was not declared in this scope."

As I know, arduino uses AVR microcontrollers, so why can't we use AVR code in arduino boards?

Answer 1

User261391 has the first issue with your code. You will then quickly find you also need to include delay.h for the delay to work.

Revised Example:

#include<avr/io.h>
#include<avr/delay.h>
void setup()
{
    DDRB = 0xFF;
}
void loop()
{
    PORTB = 0xAA;
    _delay_ms(1000);
    PORTB = 0x55;
    _delay_ms(1000);
}