Feiling OK3568-C development board USB application development based on libusb

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Feiling OK3568-C development board USB application development based on libusb [Copy link]

1. Introduction

This article introduces the application development based on libusb for OK3568-C development board, and introduces two ways: building libusb library, linking application to libusb library, and directly compiling libusb source code and application source code together. It also introduces the use of GDB for debugging.

2. How to build the library

2.1 Component Library

Download source code

git clone https://github.com/libusb/libusb.git

Enter the source code path

cd libusb/

Automatic generated

./autogen.sh

Configuration

./configure

Build and Install

make && make install

2.2 Testing

Sample code testing using source code

Enter the sample code path

cd examples/

Compile

make

Running the test program

Make compiles many test programs, such as running listdevs

./listdevs

Print as follows

root@ok3568:~/Desktop/libusb/examples# ./listdevs

1d6b:0003 (bus 8, device 1)

1d6b:0002 (bus 7, device 1)

1d6b:0003 (bus 6, device 1)

1d6b:0002 (bus 5, device 1)

1d6b:0001 (bus 4, device 1)

1d6b:0002 (bus 2, device 1)

1d6b:0001 (bus 3, device 1)

1d6b:0002 (bus 1, device 1)

2.3 Manual compilation

The examples directory above provides a Makefile for compiling all the examples. We can also manually compile our own applications or a sample program. For example, -lusb-1.0 links to the libusb library, -I specifies the header file path, and -L specifies the library file path.

gcc listdevs.c -I../libusb -lusb-1.0 -L../libusb

2.4 Debugging

Install gdb

apt install gdb

-g compile

gcc listdevs.c -I../libusb -lusb-1.0 -L../libusb-g -o listdevs

Debugging with gdb

gdb listdevs

3. Use source code directly

The above method of building the library first and then linking the library does not allow you to see the source code of libusb during debugging. We can directly use the source code of libusb and compile it together with our own application code, which makes it easier to debug and read the source code.

Copy the contents to your own project directory

Copy the following content under libusb

core.c

descriptor.c

hotplug.c

I.c

libusb.h

libusbi.h

sync.c

version.h

version_nano.h

strerror.c

Copy the following content under libusb/os

events_posix.c

events_posix.h

linux_udev.c

linux_usbfs.c

linux_usbfs.h

threads_posix.c

threads_posix.h

listdevs.c under examples

At the same time, copy the config.h file

The final directory is as follows

.

|-- examples

| |-- config.h

| `-- listdevs.c

`-- libusb

|-- core.c

|-- descriptor.c

|-- hotplug.c

|-- i.c

|-- libusb.h

|-- libusbi.h

|-- the

| |-- events_posix.c

| |-- events_posix.h

| |-- linux_udev.c

| |-- linux_usbfs.c

| |-- linux_usbfs.h

| |-- threads_posix.c

| `-- threads_posix.h

|-- strerror.c

|-- sync.c

|-- version.h

`-- version_nano.h

3 directories, 19 files

The compilation command is as follows

cd examples

gcc ../libusb/*.c ../libusb/os/events_posix.c ../libusb/os/linux_udev.c ../libusb/os/linux_usbfs.c ../libusb/os/threads_posix.c ./listdevs.c -I../libusb -I../libusb/os -I./ -lpthread -ludev -g -o listdevs

gcc libusb/*.c libusb/os/events_posix.c libusb/os/linux_udev.c libusb/os/linux_usbfs.c libusb/os/threads_posix.c ./examples/listdevs.c -Ilibusb -Ilibusb/os -Iexamples - lpthread -ludev -g -o listdevs

Debugging with GDB

gdb listdevs

Print as follows

root@ok3568:~/Desktop/libusbtest/examples# gdb listdevs

GNU gdb (Ubuntu 9.2-0ubuntu1~20.04.1) 9.2

Copyright (C) 2020 Free Software Foundation, Inc.

License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law.

Type "show copying" and "show warranty" for details.

This GDB was configured as "aarch64-linux-gnu".

Type "show configuration" for configuration details.

For bug reporting instructions, please see:

<http://www.gnu.org/software/gdb/bugs/>.

Find the GDB manual and other documentation resources online at:

<http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".

Type "apropos word" to search for commands related to "word"...

Reading symbols from listdevs...

(gdb)

layout srcOpen source view

b main breaks the function in main

(gdb) b main

Breakpoint 1 at 0x178cc: file ./listdevs.c, line 53.

(gdb)

Enter run and press Enter to execute to the breakpoint

Press s to run in single step to enter the source code of libusb for debugging

• Summarize

It is relatively simple to use libusb under Linux. There is not much source code for libusb. In the development stage, it is recommended to compile it directly with the application code for easy debugging. It depends on libpthread libudev.

From the above, we can see that thanks to the powerful performance and perfect environment of OK3568-C, USB application development can be carried out conveniently.