Ubuntu下调试USB通信

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我是靠谱客的博主义气金毛，最近开发中收集的这篇文章主要介绍Ubuntu下调试USB通信，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

环境：Ubuntu 16，libusb1.0.22

测试对象：U盘

程序源代码：

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

#include "libusb.h"

static struct libusb_device_handle *devh = NULL;
static unsigned char imgbuf[4] = {'a','b','c','d'};
unsigned char imgbuf_rx[4]={'e','e','e','e'};

static int find_print_device(void)
{
   devh = libusb_open_device_with_vid_pid(NULL,0xffff,0x1201);//luo ji webcam id;(NULL,0x046d,0x0825);//
   fprintf(stderr, "open_devh %dn", devh?0:EIO);
   return devh ? 0 : -EIO;
}

int main(void)
{
   int r;
   int count = 0;
   int count_rx = 0;
   r = libusb_init(NULL);
   if (r < 0) {
       fprintf(stderr, "failed to initialise libusbn");
       exit(1);
   }

   r = find_print_device();
   if (r < 0) {
       fprintf(stderr, "Could not find/open devicen");
       goto out;
   }

   r = libusb_claim_interface(devh, 0);
   {
   if(r<0)
   {
       r = libusb_detach_kernel_driver(devh,0);

       if (r < 0)
       {
           fprintf(stderr, "libusb_detach_kernel_deriver failed! %dn", r);
           goto out;
       }
       r = libusb_claim_interface(devh, 0);

       if (r < 0) {
           fprintf(stderr, "usb_claim_interface error %dn", r);
           goto out;
       }
}
   }

printf("claimed interface successed!n");

   r = libusb_bulk_transfer(devh,0x01,imgbuf,sizeof(imgbuf),&count,0);

   if (r < 0)
   {
       fprintf(stderr, "Could not bulk transfer!n");
       goto out0;
   }
   else
   {
       fprintf(stderr, "bulk transfer successed!,count = %dn",count);
   }

   for(int i = 0;i<4;i++)
   {
       fprintf(stderr, "imgbuf is %cn", imgbuf[i]);
   }

   r = libusb_bulk_transfer(devh,0x82,imgbuf_rx,sizeof(imgbuf_rx),&count_rx,2); //test usb read in and printf the test result 20200907

   if (r < 0)
   {
       fprintf(stderr, "Could not bulk transfer_rx! %dn",r);
       goto out0;
   }
   else
   {
       fprintf(stderr, "bulk transfer_rx successed!,count_rx = %dn",count_rx);
   }

   for(int i = 0;i<4;i++)
   {
       fprintf(stderr, "imgbuf_rx is %cn", imgbuf_rx[i]);
   }

out0:
   libusb_release_interface(devh, 0);
   libusb_detach_kernel_driver(devh,0);
out:
   libusb_close(devh);
   libusb_exit(NULL);
   return r >= 0 ? r : -r;
}

测试结果：

1、成功将数据写入U盘。

2、再将数据读出失败，返回值 -9.

疑问是不是U盘坏掉了？明明端点都是正确的。

发现U盘虽然有端点（如0x81）显示bulk类型支持，实际操作时返回 -9的原因时不支持这种类型的数据传输。于是暂停测试，有机会再更新。