【Qt】使用libusb和hidapi实现hid通信

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        使用libusb可以实现通用的usb通信，但是实现较为复杂，可以使用hidapi来封装一层，通过hidapi调用libusb。
        具体流程如下：

1、编译libusb
下载地址：https://sourceforge.net/projects/libusb/files/libusb-1.0/
编译时，要加 --disable-udev参数，我们不使用这个lib
若是给本机使用：

./configure --prefix=/opt/libusb1.0 --disable-udev
make
make install

若是交叉编译给arm开发板用

./configure --build=i686-linux --host=arm-linux --prefix=·pwd·/install  CC=arm-linux-gcc CXX=arm-linux-g++ --disable-udev
make
make install

2、复制lib到系统lib环境中

cp /opt/libusb1.0/lib/libusb-1.0.so* /usr/lib

3、使用hidapi
下载地址：https://github.com/signal11/hidapi/downloads，下载0.7版本
解压之后会发现里面有很多文件夹，例如hidapi, hidtest, linux, windows，其中hidapi是共用部分，linux下面有makefile，可以编译出linux下可以使用的hid读写的hidtest程式，读写的对象是vid为0x04d8，pid为0x003f。
编译demo需要修改makefile以支持我们编译的libusb路径查找。
修改内容如下：

#LIBS      = '`pkg-config libusb-1.0 libudev --libs`'
LIBS      = -L"/usr/lib/x86_64-linux-gnu" -lusb-1.0 -lpthread
#INCLUDES ?= -I../hidapi `pkg-config libusb-1.0 --cflags`
INCLUDES ?= -I../hidapi  -I/opt/libusb1.0/include/libusb-1.0

然后make & make install


如果使用Qt，则复制3个文件，添加到工程中，hidapi文件夹下的hidapi.h，这个主要是结构体的封装，linux下的hid-libusb.c，这个主要是一些主体调用函数，hidtest中的hidtest.cpp，这个主要是测试的demo，可以直接修改自己使用，当然，不修改也可以使用demo。
编译是需要用到libusb，所以要在.pro文件中添加对应的头文件目录和lib目录，在最后面新增两行如下：

INCLUDEPATH += /opt/libusb1.0/include/libusb-1.0
LIBS += -L"/usr/lib/x86_64-linux-gnu" -lusb-1.0

以下为C语言写法
修改hidtest.c为MainHidInterface.c和MainHidInterface.h

使用pthread来支持多线程读写，采用回调函数来返回读到的数据。

 

MainHidInterface.h

#ifndef DeltaHIDINTERFACE_H

#define DeltaHIDINTERFACE_H

#include <stdio.h>
#include <wchar.h>
#include <string.h>
#include <stdlib.h>
#include "hidapi.h"

// Headers needed for sleeping.
#include <unistd.h>

#define hidDataLength 64

//hid data receive callback function
typedef void (*DataArriveCallBackFunc)(unsigned char *recData,unsigned char length);

DataArriveCallBackFunc hidDataArriveCallBack;

hid_device *handle;

unsigned char isOpen;


int hidApi_Init(DataArriveCallBackFunc DataArriveCallBack);

int hidApi_Write(unsigned char *data, unsigned char length);

//when data arrived, the function will be called
void hidApi_DataReceive(unsigned char *recData,unsigned char length);

int hidApi_Close(void);

#endif // HIDINTERFACE_H

MainHidInterface.c

#include "hidinterface.h"
#include <pthread.h>

void hidRead_thread(void);

int hidApi_Init(DataArriveCallBackFunc DataArriveCallBack)
{
    hidDataArriveCallBack = NULL;
    // Open the device using the VID, PID,
    // and optionally the Serial number.
    ////handle = hid_open(0x4d8, 0x3f, L"12345");
    handle = hid_open(0x4d8, 0x3f, NULL);
    if (!handle) {
        printf("unable to open device\n");
        isOpen = 0;
        return -1;
    }

    printf("open device success\n");
    isOpen = 1;
    hidDataArriveCallBack = DataArriveCallBack;
    hidRead_thread();


    // Set the hid_read() function to be non-blocking.
    hid_set_nonblocking(handle, 1);

    return 0;
}

int hidApi_Write(unsigned char *data, unsigned char length)
{
    int res;
    unsigned char realData[length+1];

    realData[0]=length;
    int i;
    for(i=0;i<length;i++)
    {
        realData[i+1]=data[i];
    }

    res = hid_write(handle, realData, length+1);
    if (res < 0) {
        printf("Unable to write()\n");
        printf("Error: %ls\n", hid_error(handle));
        return -1;
    }

    printf("write success\n");
    return 0;
}

void hidApi_DataReceive(unsigned char *recData,unsigned char length)
{
    if(hidDataArriveCallBack==NULL)
        return;

    hidDataArriveCallBack(recData,length);
}

void hidApi_Read()
{
    unsigned char recData[hidDataLength];

    int res;
    while (isOpen==1) {
        res = hid_read(handle, recData, hidDataLength);
        if (res == 0)
            ;//printf("waiting...\n");
        else if (res < 0)
        {
            printf("Unable to read()\n");
            return -1;
        }
        else
        {

            int i;

//            printf("Data read:\n   ");
//            // Print out the returned buffer.
//
//            for (i = 0; i < res; i++)
//                printf("%02hhx ", recData[i]);
//            printf("\n");

            unsigned char length = recData[0];

            unsigned char datas[length];
            for(i=0;i<length;i++)
            {
                datas[i]=recData[i+1];
            }

            hidApi_DataReceive(datas,length);
        }


        usleep(50*1000);

    }

}

void hidRead_thread(void)
{
   pthread_t id;
   int ret, i;
   ret=pthread_create(&id,NULL,(void *) hidApi_Read,NULL); // 成功返回0，错误返回错误编号
   if(ret!=0) {
       printf ("Create pthread error!\n");
       exit (1);
   }


   //pthread_join(id,NULL);

   printf ("Create pthread success!\n");
}

int hidApi_Close(void)
{
    hid_close(handle);
    isOpen = 0;
    /* Free static HIDAPI objects. */
    hid_exit();

    return 0;

}

 

若想使用Qt C++，则要将pthread换成QThread来执行阅读，同时，不要再使用回调函数，因为回调函数不支持成员函数（含有默认指针this），仅支持static函数，不利于使用多个对象实例，可以使用信号与槽的机制将接收到的数据传输出来。

 以下为Qt C++改写的范例，使用时要connect才能接收到数据。

MainHidInterface.h

#ifndef mMainHIDINTERFACE_H
#define mMainHIDINTERFACE_H

#include <iostream>
#include <QThread>
#include <QCoreApplication>
#include "hidapi.h"

// Headers needed for sleeping.
#include <unistd.h>

using namespace std;

#define hidDataLength 64

//typedef void (*DataRecCallbackFunc)(unsigned char *recData,unsigned char length);

class MainHidInterFace : public QThread
{
    Q_OBJECT

public:
    //Initial and set hid data receive callback function
    MainHidInterFace();

    int hidApi_Write(unsigned char *data, unsigned char length);

    int hidApi_Close(void);

signals:
    void hidDataArrived(unsigned char *data, unsigned char length);

private:


    hid_device *handle;

    unsigned char isOpen;

protected:
    void run() ;


};
#endif // HIDINTERFACE_H

MainHidInterface.cpp

/*******************************************************
 Windows HID simplification

 Alan Ott
 Signal 11 Software

 8/22/2009

 Copyright 2009, All Rights Reserved.
 
 This contents of this file may be used by anyone
 for any reason without any conditions and may be
 used as a starting point for your own applications
 which use HIDAPI.
********************************************************/


#include "hidinterface.h"

MainHidInterFace::MainHidInterFace()
{

    // Open the device using the VID, PID,
    // and optionally the Serial number.
    ////handle = hid_open(0x4d8, 0x3f, L"12345");
    handle = hid_open(0x4d8, 0x3f, NULL);
    if (!handle) {
        printf("unable to open device\n");
        isOpen = 0;
        return;
    }

    printf("open device success\n");
    isOpen = 1;

    // Set the hid_read() function to be non-blocking.
    hid_set_nonblocking(handle, 1);

    emit hidDataArrived(NULL,0);

    return;
}


int MainHidInterFace::hidApi_Write(unsigned char *data, unsigned char length)
{
    int res;
    unsigned char realData[length+1];

    realData[0]=length;
    int i;
    for(i=0;i<length;i++)
    {
        realData[i+1]=data[i];
    }

    res = hid_write(handle, realData, length+1);
    if (res < 0) {
        printf("Unable to write()\n");
        printf("Error: %ls\n", hid_error(handle));
        return -1;
    }

    printf("write success\n");
    return 0;
}


void MainHidInterFace::run()
{
    unsigned char recData[hidDataLength];

    int res;
    while (isOpen==1) {
        res = hid_read(handle, recData, hidDataLength);
        if (res == 0)
            ;//printf("waiting...\n");
        else if (res < 0)
        {
            printf("Unable to read()\n");
            return;
        }
        else
        {

            int i;

//            printf("Data read:\n   ");
//            // Print out the returned buffer.
//
//            for (i = 0; i < res; i++)
//                printf("%02hhx ", recData[i]);
//            printf("\n");

            unsigned char length = recData[0];

            unsigned char datas[length];
            for(i=0;i<length;i++)
            {
                datas[i]=recData[i+1];
            }

            emit hidDataArrived(datas,length);


        }


        usleep(50*1000);

    }

}


int MainHidInterFace::hidApi_Close(void)
{
    hid_close(handle);
    isOpen = 0;
    /* Free static HIDAPI objects. */
    hid_exit();

    delete handle;
    return 0;

}