【Qt】使用libusb和hidapi实现hid通信

        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-udevmakemake 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-udevmakemake 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-1.0LIBS += -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 functiontypedef 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 calledvoid 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_OBJECTpublic:    //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;}