树莓派使用c语言点亮led

树莓派还有一个很重要的部分就是GPIO，今天说一个简单的，在树莓派上使用c语言点亮led。

这里使用的库是wiringpi，安装wiringpi。

sudo apt-get install wiringpi

然后使用 gpio readall 查看引脚定义

root@raspberrypi:~# 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 | 0 | IN   | 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--+---+------+---------+-----+-----+

我们使用物理3号引脚（wiringpi编号为8）连接led的正极，使用物理引脚9连接负极。

代码如下：

#include <stdio.h>
#include <wiringPi.h>
int main(void)
{
        int LED = 8;
        wiringPiSetup();
        pinMode(LED,OUTPUT);
        int number = 10;
        int count = 0;
        while(count <20)
        {
                printf("LED:%d is on\n",LED);
                digitalWrite(LED,HIGH);
                delay(1000);
                printf("LED:%d is off\n",LED);
                digitalWrite(LED,LOW);
                delay(1000);
                count++;
        }
        return 0;
}

这个程序的作用就是使led闪10次，每次亮1s，熄灭1s。

进行编译。

gcc -o led -lwiringPi led.c

执行

./led

你会看到你所设定的情景，输出如下

root@raspberrypi:~# ./led
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off
LED:8 is on
LED:8 is off