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
[email protected]:~# 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
[email protected]:~# ./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
