ros中通过/sys/class/gpio读写gpio口

参考：

Ubuntu GPIO操作

inux sys gpio 读写,linux下对/sys/class/gpio中的gpio的控制 (转)

1、/sys/class/gpio常用指令

#查看gpio口信息
sudo cat /sys/kernel/debug/gpio 
#导入gpio口
sudo echo 33 > /sys/class/gpio/export
#导出gpio口
sudo echo 33 > /sys/class/gpio/unexport
#查看指定gpio口状态
sudo cat /sys/kernel/debug/gpio| grep '258'

echo out > /sys/class/gpio/gpio33/direction

定义GPIO1_A1输入输出方向， direction接受的参数：in, out, high, low。high/low同时设置方向为输出，并将value设置为相应的1/0。

echo 1 >/sys/class/gpio/gpio33/value

定义GPIO1_A1 Value值（0,1）

2、ros中读gpio

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ros/ros.h>
#include <std_msgs/Header.h>

int num=290;

int main(int argc, char** argv)
{
	//ros节点初始化
	ros::init(argc, argv, "gpio");//启动该节点并设置其名称，名称必须唯一
	ros::NodeHandle n;//设置节点进程的句柄
	ros::Rate loop_rate(1);//设置循环的频率
	
	FILE *p	= NULL;
	try{
		p = fopen( "/sys/class/gpio/export", "w" );
		fprintf( p, "%d", num );
		fclose( p );
	}
	catch(char *str){}

	
	p = fopen( "/sys/class/gpio/gpio290/direction", "w" );
	fprintf( p, "out" );
	fclose( p );

	while(ros::ok()){
		p = fopen( "/sys/class/gpio/gpio290/value", "w" );
		fprintf( p, "%d", 1 );
		printf("H\n");
		loop_rate.sleep();//按照10Hz的频率将程序挂起
		fclose( p );

		p = fopen( "/sys/class/gpio/gpio290/value", "w" );
		fprintf( p, "%d", 0 );
		printf("L\n");
		loop_rate.sleep();//按照10Hz的频率将程序挂起
		fclose( p );
	}

}

3、ros中写gpio

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ros/ros.h>
#include <std_msgs/Header.h>

int num=290;
char buffer[1];

int main(int argc, char** argv)
{
	//ros节点初始化
	ros::init(argc, argv, "gpio");//启动该节点并设置其名称，名称必须唯一
	ros::NodeHandle n;//设置节点进程的句柄
	ros::Rate loop_rate(1);//设置循环的频率
	
	FILE *p	= NULL;
	try{
		p = fopen( "/sys/class/gpio/export", "w" );
		fprintf( p, "%d", num );
		fclose( p );
	}
	catch(char *str){}

	
	p = fopen( "/sys/class/gpio/gpio290/direction", "w" );
	fprintf( p, "in" );
	fclose( p );

	while(ros::ok()){
		p = fopen( "/sys/class/gpio/gpio290/value", "r" );

		//fseek(p, 0, SEEK_SET);

		// 读取并显示数据 
		fread(buffer, 1, 1, p);
		printf("%s\n", buffer);
		loop_rate.sleep();//按照10Hz的频率将程序挂起
		fclose( p );
	}

}