Atmega2560 base course (3) - I / O input and output port

Atmega2560 base course (3) - I / O input and output port

Configuration I / O, typically requires three registers DDRx, PINx, PORTx, to I / O port A Case Study

1.I / O port output

Configuring the I / O direction is output, a high DDRx direction register their respective locations, determined by the level of the output PORTx

/*
	PA0输出引脚，10ms翻转一次电平
*/
#define F_CPU 16000000UL
#include <avr/io.h>
#include <util/delay.h>
int main(void)
{
	DDRA|=_BV(DDA0);
	PORTA|=_BV(DDA0);
	_delay_ms(10);
	while (1)
	{
		PORTA&=~_BV(DDA0);
		_delay_ms(10);
		PORTA|=_BV(DDA0);
		_delay_ms(10);
	}
}

Waveform diagram as follows:

2.I / O port input

Configuring I / O port as an input, low DDRx direction register their respective locations, the input level can be read by a PINx, PORTx determined level when no input

/*
	PA0输入引脚，无输入时为高电平，PD0输出引脚，PA0输入低电平时PD0输出低电平，
	PA0输入高电平时PD0输出高电平
*/
#define F_CPU 16000000UL
#include <avr/io.h>
#include <util/delay.h>
#include <avr/sfr_defs.h>
int main(void)
{
	DDRA&=~_BV(DDA0);
	PORTA|=_BV(PA0);
	DDRD|=_BV(DDD0);
	PORTD|=_BV(PD0);
	while (1)
	{
		if (bit_is_clear(PINA,PINA0))
		  {
			  PORTD&=~_BV(PD0);
		  }
		  else
		  {
			  PORTD|=_BV(PD0);
		  }
	}
}