Download, compile and install libusb: https://blog.csdn.net/u011598479/article/details/82705378
1. Determine some parameters of the USB device you want to communicate with.
user_device.idProduct = USB_PRODUCT_ID; //PID
user_device.idVendor = USB_VENDOR_ID ; //VID
user_device.bInterfaceClass = LIBUSB_CLASS_PRINTER; //printer device
user_device.bInterfaceSubClass = LIBUSB_CLASS_PER_INTERFACE ; //reserved interface
user_device.bmAttributes = LIBUSB_TRANSFER_TYPE_BULK ; //usb bulk communication method
user_device.dev = NULL; //Initialization parameters
user_device is the structure I set up to save some parameters to be used.
2.init_libusb(); //Call this library function to initialize the library
3. Obtain the device descriptor, and then traverse the configuration descriptor, interface descriptor, and endpoint descriptor according to the device parameters in the first step to find the endpoint address of the USB device
4. Open the device libusb_open_device_with_vid_pid()
5. Declare the interface libusb_claim_interface()
6. Send data libusb_bulk_transfer()
7. Close the device, release the interface, release the requested space, and exit the library
libusb_close(g_usb_handle);
libusb_release_interface(g_usb_handle,user_device.bInterfaceNumber);
libusb_free_device_list(user_device.devs, 1);
libusb_exit(NULL);
Makefile
# C compiler options
CC = gcc
#CFLAGS = -g -O2
TARGET = main
LIBSPATH = ../lib
PLATFORM = linux32
#LIBS = /usr/local/lib -lusb-1.0
LIBS = /usr/local/lib/libusb-1.0.a -lm -lpthread
INC = /usr/local/include/libusb-1.0
#多字节字符 指定汉字编码方式GB18030
EXCHAR = -fexec-charset=GB18030
# Source files
SRCS = main.c
# Object files
OBJS = $(SRCS:.c=.o)
# Make everything
all: $(TARGET)
# Make the application
#-lstdc++:编译c++的时候用到
$(TARGET): $(OBJS)
$(CC) $(CFLAGS) $(EXCHAR) -o $(TARGET) $(OBJS) $(LIBS)
# Dependencies
#$@:表示目标文件，即：demo.o
#$<：表示依赖文件，即：demo.c
#-I$(INC) :指向包含了的.h文件的路径 即wbe,h的路径
$(OBJS): %.o: %.c
$(CC) -c $(CFLAGS) $(EXCHAR) -o $@ $< -I$(INC)
#
# Clean all object files...
#
clean:
$(RM) $(OBJS) $(TARGET)
main.c
/*
* libusb example program to list devices on the bus
* Copyright © 2007 Daniel Drake <[email protected]>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include "libusb.h"
#define USB_VENDOR_ID 0x0483
#define USB_PRODUCT_ID 0x8007
#define BULK_ENDPOINT_OUT 1
#define BULK_ENDPOINT_IN 2
struct userDevice{
/*Device descriptor*/
/** USB-IF vendor ID */
uint16_t idVendor;
/** USB-IF product ID */
uint16_t idProduct;
/*Interface descriptor*/
/** USB-IF class code for this interface. See \ref libusb_class_code. */
uint8_t bInterfaceClass;
/** USB-IF subclass code for this interface, qualified by the
* bInterfaceClass value */
uint8_t bInterfaceSubClass;
/*Endpoint descriptor*/
/** Attributes which apply to the endpoint when it is configured using
* the bConfigurationValue. Bits 0:1 determine the transfer type and
* correspond to \ref libusb_transfer_type. Bits 2:3 are only used for
* isochronous endpoints and correspond to \ref libusb_iso_sync_type.
* Bits 4:5 are also only used for isochronous endpoints and correspond to
* \ref libusb_iso_usage_type. Bits 6:7 are reserved.
*/
uint8_t bmAttributes;
/*save parameter*/
libusb_device *dev;
libusb_device **devs;
u_int8_t bInEndpointAddress;
u_int8_t bOutEndpointAddress;
/* Number of this interface */
uint8_t bInterfaceNumber;
};
int init_libusb(void)
{
/*1. init libusb lib*/
int rv = 0;
rv = libusb_init(NULL);
if(rv < 0) {
printf("*** initial USB lib failed! \n");
return -1;
}
return rv;
}
int get_device_descriptor(struct libusb_device_descriptor *dev_desc,struct userDevice *user_device)
{
/*2.get device descriptor*/
int rv = -2;
ssize_t cnt;
int i = 0;
libusb_device **devs;
libusb_device *dev;
cnt = libusb_get_device_list(NULL, &devs); //check the device number
if (cnt < 0)
return (int) cnt;
while ((dev = devs[i++]) != NULL) {
rv = libusb_get_device_descriptor(dev,dev_desc);
if(rv < 0) {
printf("*** libusb_get_device_descriptor failed! i:%d \n",i);
return -1;
}
if(dev_desc->idProduct==user_device->idProduct &&dev_desc->idVendor==user_device->idVendor)
{
user_device->dev = dev;
user_device->devs = devs;
rv = 0;
break;
}
}
return rv;
}
int match_with_endpoint(const struct libusb_interface_descriptor * interface, struct userDevice *user_device)
{
int i;
int ret=0;
for(i=0;i<interface->bNumEndpoints;i++)
{
if((interface->endpoint[i].bmAttributes&0x03)==user_device->bmAttributes) //transfer type :bulk ,control, interrupt
{
if(interface->endpoint[i].bEndpointAddress&0x80) //out endpoint & in endpoint
{
ret|=1;
user_device->bInEndpointAddress = interface->endpoint[i].bEndpointAddress;
}
else
{
ret|=2;
user_device->bOutEndpointAddress = interface->endpoint[i].bEndpointAddress;
}
}
}
if(ret==3)
{
return 1;
}
else
{
return 0;
}
}
int get_device_endpoint(struct libusb_device_descriptor *dev_desc,struct userDevice *user_device)
{
/*3.get device endpoint that you need */
int rv = -2;
int i,j,k;
struct libusb_config_descriptor *conf_desc;
u_int8_t isFind = 0;
for (i=0; i< dev_desc->bNumConfigurations; i++)
{
if(user_device->dev != NULL)
rv = libusb_get_config_descriptor(user_device->dev,i,&conf_desc);
if(rv < 0) {
printf("*** libusb_get_config_descriptor failed! \n");
return -1;
}
for (j=0; j< conf_desc->bNumInterfaces; j++)
{
for (k=0; k < conf_desc->interface[j].num_altsetting; k++)
{
if(
conf_desc->interface[j].altsetting[k].bInterfaceClass==user_device->bInterfaceClass
)
{
if(match_with_endpoint(&(conf_desc->interface[j].altsetting[k] ), user_device ))
{
user_device->bInterfaceNumber = conf_desc->interface[j].altsetting[k].bInterfaceNumber;
libusb_free_config_descriptor(conf_desc);
rv = 0;
return rv;
}
}
}
}
}
return -2; //don't find user device
}
int main(void)
{
int rv;
int length;
unsigned char a[100] = {0x0a,0x0a,0x0a,0x0a,0x0a,0x0a,0x0a,0x0a,0x0a,0x0a};
libusb_device_handle* g_usb_handle;
struct userDevice user_device;
struct libusb_device_descriptor dev_desc;
user_device.idProduct = USB_PRODUCT_ID;
user_device.idVendor = USB_VENDOR_ID ;
user_device.bInterfaceClass = LIBUSB_CLASS_PRINTER ;
user_device.bInterfaceSubClass = LIBUSB_CLASS_PRINTER ;
user_device.bmAttributes = LIBUSB_TRANSFER_TYPE_BULK ;
user_device.dev = NULL;
init_libusb();
rv = get_device_descriptor(&dev_desc,&user_device);
if(rv < 0) {
printf("*** get_device_descriptor failed! \n");
return -1;
}
rv = get_device_endpoint(&dev_desc,&user_device);
if(rv < 0) {
printf("*** get_device_endpoint failed! rv:%d \n",rv);
return -1;
}
/*4.open device and start communication by usb*/
//open the usb device
g_usb_handle = libusb_open_device_with_vid_pid(NULL, user_device.idVendor, user_device.idProduct);
if(g_usb_handle == NULL) {
printf("*** Permission denied or Can not find the USB board (Maybe the USB driver has not been installed correctly), quit!\n");
return -1;
}
rv = libusb_claim_interface(g_usb_handle,user_device.bInterfaceNumber);
if(rv < 0) {
rv = libusb_detach_kernel_driver(g_usb_handle,user_device.bInterfaceNumber);
if(rv < 0) {
printf("*** libusb_detach_kernel_driver failed! rv%d\n",rv);
return -1;
}
rv = libusb_claim_interface(g_usb_handle,user_device.bInterfaceNumber);
if(rv < 0)
{
printf("*** libusb_claim_interface failed! rv%d\n",rv);
return -1;
}
}
rv = libusb_bulk_transfer(g_usb_handle,BULK_ENDPOINT_OUT,a,100,&length,1000);
if(rv < 0) {
printf("*** bulk_transfer failed! \n");
return -1;
}
libusb_close(g_usb_handle);
libusb_release_interface(g_usb_handle,user_device.bInterfaceNumber);
libusb_free_device_list(user_device.devs, 1);
libusb_exit(NULL);
}