探索Wiring Pi

wIring pi ，专门为树莓派打造的类似于arduino下的wiring驱动库

安装好这个库后可以直接调用函数配置和控制GPIO功能

（无论是用c shell  python都能控制GPIO了）

树莓派有个26pin的扩展端子（树莓派V2旁边还有个8pin的没焊接的端口也可自己焊接使用）

其中电源包含3.3v  5v  Gnd

可以控制的资源有

SPI,IIC,UART,通用GPIO.（其中一个可做PWM）

第一部分，库的情况和获取

快速安装（c开发库）

mkdir temp
cd temp
wget http://project-downloads.drogon.net/files/wiringPi.tgz
tar xf wiringPi.tgz
cd wiringPi/wiringPi/
make
make install

官方给的安装方式： https://projects.drogon.net/raspberry-pi/wiringpi/download-and-install/

wiringpi

 

1.1.0

WiringPi library wrapper for the Raspberry Pi only. Wraps up the Arduino wiring-like WiringPi library into a convinient Ruby gem. Currently includes GPIO functionality, serial and shiftOut/shiftIn support. Credit to Gordon for the WiringPi library, which can be found here: http://projects.drogon.net/raspberry-pi/wiringpi/

        wiring pi项目网站https://projects.drogon.net/raspberry-pi/wiringpi/

          树莓派官方：http://www.raspberrypi.org/

在Github项目

https://github.com/WiringPi

第二部分：库的初始化和引脚重定义机制

库的初始化函数可以是以下三个中的一个

• int wiringPiSetup (void) ;                //使用IO映射，可以更方便的管理IO   需要root权限
  
• int wiringPiSetupGpio (void) ;      //不用映射直接用物理IO编号                需要root权限
  
• int wiringPiSetupSys (void) ;         //不需要root权限
• 另外库还支持命令行模式直接用shell脚本就可以控制GPIO

如果你用

• wiringPiSetup (void) 初始化

• 则引脚被重新定义/映射（DNC的意思是不要连接）

具体可参考https://projects.drogon.net/raspberry-pi/wiringpi/pins/

• 
  P5: The auxilliary GPIO connector present on Rev. 2 boards only:Board Revisions: Please note the differences between board revisions 1 and 2 (R1 and R2 above)

左边是wiring库封装后对应的引脚    右边是树莓派的物理真实引脚 

所以比如下面的例子，你用wiring库中的函数操作gpio4 其实是操作物理端口的GPIO23

第三部分：一个简单的实例

.c引入头文件

初始化库

控制IO口

另外：编译时加上库

(用wiring库操作LED的实例http://www.codelast.com/?p=5155）

实例一
用C语言控制

// led.c
 
#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>
 
int main (int argc,char* argv[])
{
  if (argc < 2) {
    printf("Usage example: ./led 4 \n");
    return 1;
  }
  int pinNumber = atoi(argv[1]);
 
  if (-1 == wiringPiSetup()) {
    printf("Setup wiringPi failed!");
    return 1;
  }
 
  pinMode(pinNumber, OUTPUT); // set mode to output 
  while(1) {
    digitalWrite(pinNumber, 1); // output a high level 
    delay(800);
    digitalWrite(pinNumber, 0); // output a low level 
    delay(800);
  }
 
  return 0;
}

#gcc led.c -o led - lwiringPi

#./led4







实例二

最简单的python控制

$ sudo python
>>> import RPi.GPIO as GPIO
>>> GPIO.setup(18, GPIO.OUT)
>>> GPIO.output(18, False)

实例三

用python控制

import RPi.GPIO as GPIO
import time

# Use physical pin numbers
GPIO.setmode(GPIO.BOARD)
# Set up header pin 11 (GPIO17) as an input
print "Setup Pin 11"
GPIO.setup(11, GPIO.OUT)

var=1
print "Start loop"
while var==1 :
  print "Set Output False"
  GPIO.output(11, False)
  time.sleep(1)
  print "Set Output True"
  GPIO.output(11, True)
  time.sleep(1)

实例4 PWM输出

/*
 * test2.c:
 *	Simple test program to test the wiringPi functions
 *	PWM test
 */

#include <wiringPi.h>

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

int main (void)
{
  int bright ;

  printf ("Raspberry Pi wiringPi PWM test program\n") ;

  if (wiringPiSetup () == -1)
    exit (1) ;

  pinMode (1, PWM_OUTPUT) ;

  for (;;)
  {
    for (bright = 0 ; bright < 1024 ; ++bright)
    {
      pwmWrite (1, bright) ;
      delay (1) ;
    }

    for (bright = 1023 ; bright >= 0 ; --bright)
    {
      pwmWrite (1, bright) ;
      delay (1) ;
    }
  }

  return 0 ;
}




第四部分：文件夹内容以及api函数

text

git：git版本管理

examples：实例包括延时测试。PWM,（test2）GPIO（test1控制测试所有IO）,LCD,串口，中断等，

gpio：UTILITY模式下控制GPIO test.sh

wiringpi：库函数实现

https://projects.drogon.net/raspberry-pi/wiringpi/

WiringPi Resources

• Raspberry Pi GPIO Pin numbering
• WiringPi Functions/API documentation
• The GPIO Utility

Additional Libraries

• Serial port handling (both on-board and USB)
• LCD library
• Software PWM library
• Shift library
• Simplified SPI handling library
• Simplified I2C handling library
• GPIO Interrupt Handling

The PiFace board:

WiringPi fully supports the PiFace board too. See this page for more details.

Other wiringPi resources:

• Thanks to Gadgetoid there are now wrappers for Ruby, Python and Perl and these can all befound here.
• Thanks to Jeroen Kransen there are wrappers for Java which can be found here.
• Thanks to Dave Boulton for creating a TCL wrapper  which can be found here.
• Pi4J is another Java project that uses WiringPi. It has a Github repository here.

Pin numbering

WiringPi supports both an Arduino style pin numbering scheme which numbers the pins sequentially from 0 upwards, as well as the Raspberry Pi’s native BCM_GPIO pin numbering scheme.

• Note that when using the BCM_GPIO numbering scheme, you must take into account the board revision! Some pins changed their meaning and numbers from revision 1 to revision 2. Using the wiringPi pin numbering scheme caters for these changes and progams will run un-changed on their board revision.

WiringPi normally uses a very low-level mechanism to access the underlying hardware – this results in very fast access, however the down-side is that your programs need to be run as root, so in addition to this, wiringPi has the ability to use the traditional /sys/class/gpio/ style interface, and if the GPIO pins have been exported and had their ownership changed appropriately, then applications using the wiringPi library, can be run without root privileges.

A supporting program, gpio, allows you to export and unexport the devices through the/sys/class/gpio/ interface. This program is a set-uid program and can be run as a normal user. The gpio program can be used to control the GPIO pins in its own right, allowing easy testing of the GPIO interface from the command-line or simple shell scripts.

• See the pins page for a description of the WiringPi pin to GPIO connector mappings, and take note of the…
• … special pin functions too.
• The Functions page lists and documents what’s available, and
• There are some examples here too.
• Download and Install

Additional information can be found on the Raspberry Pi Wiki pages.