玩转树莓派（五）使用C语言 通过wiringPi库控制GPIO

玩转树莓派（五）使用C语言 通过wiringPi库控制GPIO

一、创建环境

• 新建CWorkSpace文件夹
• 新建gpio_out.c文件

pi@raspberrypi:~ $ mkdir CWorkSpace
pi@raspberrypi:~ $ cd CWorkSpace/
pi@raspberrypi:~/CWorkSpace $ vim gpio_out.c

二、编写代码

• 编辑gpio_out.c

#include <wiringPi.h>
#include <stdio.h>

#define PIN 1

int main(void)
{
    
    
	int i=0;
	wiringPiSetup();
	pinMode (PIN, OUTPUT);
	for(i=0;i<10;i++)
	{
    
    
		printf("gpio out: %d\r\n", i);
		digitalWrite(PIN, i%2); 
		delay(3000);
	}
	printf("gpio out end\r\n");
	return 0;
}

三、编译运行

• 编译，编译时要连接wiringPi的库
• 运行

pi@raspberrypi:~/CWorkSpace $ gcc -o gpio_out gpio_out.c -lwiringPi
pi@raspberrypi:~/CWorkSpace $ ./gpio_out 
gpio out: 0
gpio out: 1
gpio out: 2
gpio out: 3
gpio out: 4
gpio out: 5
gpio out: 6
gpio out: 7
gpio out: 8
gpio out: 9
gpio out end

四、查看效果

用万用表量下编号12的GPIO.1的引脚，可以发现其间隔3s的高低电平变换了10次。

• 手边如果一时半会找不到树莓派的GPIO引脚图
• 可以通过gpio readall查看

pi@raspberrypi:~/PythonWorkSpace $ gpio readall
 +-----+-----+---------+------+---+---Pi 3B--+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 |     |     |    3.3v |      |   |  1 || 2  |   |      | 5v      |     |     |
 |   2 |   8 |   SDA.1 |   IN | 1 |  3 || 4  |   |      | 5v      |     |     |
 |   3 |   9 |   SCL.1 |   IN | 1 |  5 || 6  |   |      | 0v      |     |     |
 |   4 |   7 | GPIO. 7 |   IN | 1 |  7 || 8  | 0 | IN   | TxD     | 15  | 14  |
 |     |     |      0v |      |   |  9 || 10 | 1 | IN   | RxD     | 16  | 15  |
 |  17 |   0 | GPIO. 0 |   IN | 0 | 11 || 12 | 1 | OUT  | GPIO. 1 | 1   | 18  |
 |  27 |   2 | GPIO. 2 |   IN | 0 | 13 || 14 |   |      | 0v      |     |     |
 |  22 |   3 | GPIO. 3 |   IN | 0 | 15 || 16 | 0 | IN   | GPIO. 4 | 4   | 23  |
 |     |     |    3.3v |      |   | 17 || 18 | 0 | IN   | GPIO. 5 | 5   | 24  |
 |  10 |  12 |    MOSI |   IN | 0 | 19 || 20 |   |      | 0v      |     |     |
 |   9 |  13 |    MISO |   IN | 0 | 21 || 22 | 0 | IN   | GPIO. 6 | 6   | 25  |
 |  11 |  14 |    SCLK |   IN | 0 | 23 || 24 | 1 | IN   | CE0     | 10  | 8   |
 |     |     |      0v |      |   | 25 || 26 | 1 | IN   | CE1     | 11  | 7   |
 |   0 |  30 |   SDA.0 |   IN | 1 | 27 || 28 | 1 | IN   | SCL.0   | 31  | 1   |
 |   5 |  21 | GPIO.21 |   IN | 1 | 29 || 30 |   |      | 0v      |     |     |
 |   6 |  22 | GPIO.22 |   IN | 1 | 31 || 32 | 0 | IN   | GPIO.26 | 26  | 12  |
 |  13 |  23 | GPIO.23 |   IN | 0 | 33 || 34 |   |      | 0v      |     |     |
 |  19 |  24 | GPIO.24 |   IN | 0 | 35 || 36 | 0 | IN   | GPIO.27 | 27  | 16  |
 |  26 |  25 | GPIO.25 |   IN | 0 | 37 || 38 | 0 | IN   | GPIO.28 | 28  | 20  |
 |     |     |      0v |      |   | 39 || 40 | 0 | IN   | GPIO.29 | 29  | 21  |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+---Pi 3B--+---+------+---------+-----+-----+

五、wiringPi库简单介绍

函数	int wiringPiSetup (void)
说明	设置wiringPi的引脚编号系统
返回	-1：失败；其他：正常

函数	int wiringPiSetupGpio (void)
说明	设置BCM 的引脚编号系统
返回	-1：失败；其他：正常

函数	void pinMode (int pin, int mode)
说明	设置引脚的IO模式
输入	pin：引脚编号
——	mode：INPUT、OUTPUT、PWM_OUTPUT((仅wiringPi 1号引脚支持))，GPIO_CLOCK(仅wiringPi 7号引脚支持)

函数	void digitalWrite (int pin, int value)
说明	设置引脚的输出电平
输入	pin：引脚编号
——	value：电平状态，HIGH：高电平；LOW：低电平

六、漂亮的Ending

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