使用C语言控制 GPIO.18
首先知道树莓派外置IO的关系对照表
我这里的树莓派是： PI 3B + V1.2
关系对照表如下：
C 语言下使用 wiringPi GPIO 进行编程
要安装 wiringPi
pi@raspberrypi:~ $ sudo apt-get update
pi@raspberrypi:~ $ sudo apt-get upgrade
pi@raspberrypi:~ $ sudo apt-get install wiringpi
测试 wiringPi 是否安装成功
pi@raspberrypi:~/pilearn $ gpio -v
gpio version: 2.50
Copyright (c) 2012-2018 Gordon Henderson
This is free software with ABSOLUTELY NO WARRANTY.
For details type: gpio -warranty
Raspberry Pi Details:
Type: Pi 3, Revision: 02, Memory: 1024MB, Maker: Embest
* Device tree is enabled.
*--> Raspberry Pi 3 Model B Rev 1.2
* This Raspberry Pi supports user-level GPIO access.
使用 wiringPi 查看树莓派引脚对应关系：
pi@raspberrypi:~/pilearn $ 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 | 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--+---+------+---------+-----+-----+
树莓派的GPIO编码方式
1、功能物理引脚：
从左到右，从上到下：左边基数，右边偶数：1-40
2、BCM:
编号侧重CPU寄存器，根据BCM2835的GPIO寄存器编号。
3、wpi：
编号侧重实现逻辑，把扩展GPIO端口从0开始编号，这种编号方便编程。
代码如下：
#include <wiringPi.h>
#include <stdio.h>
int main(void) {
wiringPiSetup();
pinMode (1, OUTPUT);
for(;;) {
digitalWrite(1, HIGH);
printf("GPIO_18 IS HIGH \n");
delay (500);
digitalWrite(1, LOW);
printf("GPIO_18 IS LOW \n");
delay (500);
}
}
运行程序前需要编译，由于引入外部库，编译时要 link 相应的库
编译并执行：
pi@raspberrypi:~/pilearn $ gcc led.c -o led -l wiringPi
pi@raspberrypi:~/pilearn $ ls
led led.c
pi@raspberrypi:~/pilearn $ ./led
GPIO_18 IS HIGH
GPIO_18 IS LOW
GPIO_18 IS HIGH
GPIO_18 IS LOW
GPIO_18 IS HIGH
GPIO_18 IS LOW
GPIO_18 IS HIGH
GPIO_18 IS LOW