树莓派

wiringPi其实和BCM2835 library类似，也是通过memmap, IOmap来实现在用户空间直接操作底层寄存器

wiringPi

http://wiringpi.com/

WiringPi is a PIN based GPIO access library written in C for the BCM2835, BCM2836 and BCM2837 SoC devices used in all Raspberry Pi. versions.

在之前编译的系统中wiringPi已经预装了, gpio readall可以读出gpio

pi@raspberrypi:~ $ gpio readall
 +-----+-----+---------+------+---+---Pi 3---+---+------+---------+-----+-----+
 | BCM | wPi |   Name  | Mode | V | Physical | V | Mode | Name    | wPi | BCM |
 +-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
 |     |     |    3.3v |      |   |  1 || 2  |   |      | 5v      |     |     |
 |   2 |   8 |   SDA.1 | ALT0 | 1 |  3 || 4  |   |      | 5v      |     |     |
 |   3 |   9 |   SCL.1 | ALT0 | 1 |  5 || 6  |   |      | 0v      |     |     |
 |   4 |   7 | GPIO. 7 |   IN | 1 |  7 || 8  | 1 | ALT5 | TxD     | 15  | 14  |
 |     |     |      0v |      |   |  9 || 10 | 1 | ALT5 | RxD     | 16  | 15  |
 |  17 |   0 | GPIO. 0 |   IN | 0 | 11 || 12 | 1 | 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 3---+---+------+---------+-----+-----+

gpio在/usr/bin下

pi@raspberrypi:~ $ whatis gpio
gpio (1)             - Command-line access to Raspberry Pi's GPIO
pi@raspberrypi:~ $ whereis gpio
gpio: /usr/bin/gpio /usr/share/man/man1/gpio.1

查看lib, include, 已经安装好了

pi@raspberrypi:/usr/lib $ ls |grep wiringPi
libwiringPiDev.so
libwiringPiDev.so.2.44
libwiringPi.so
libwiringPi.so.2.44

pi@raspberrypi:/usr/include $ ls | grep wiringPi
wiringPi.h
wiringPiI2C.h
wiringPiSPI.h

将led.c copy到树莓派，编译，生成led, 执行，闪灯

#include<wiringPi.h>

char LED = 25;

int main(void)
{
	if(wiringPiSetup() < 0)return 1;
	pinMode (LED,OUTPUT) ;

	while(1)
	{
  		digitalWrite(LED, 1) ;
    	delay (200);
  		digitalWrite(LED, 0) ;
    	delay (200);
	}
}

makefile

led:led.c
	gcc -Wall led.c -o led -lwiringPi
	gcc -Wall pwm.c -o pwm -lwiringPi
clean:
	rm led pwm