USB protocol analysis, usb protocol
1. Description structure of USB devices
1. Logical Organizational Structure
The logical organization of a USB device consists of four layers: device, configuration, interface, and endpoint. A device usually has one or more configurations. The configuration usually has one or more int
"Come out and try again sooner or later ."
Basically, LinuxEach directory in the kernel has a makefile. MakefileAnd kconfigJust like a map of a city, a map leads us to know a city, while makefileAnd kconfigSo that we can understand the structure under this directory. Drivers/USB/storage/Makefile under the DirectoryThe content is as follows:
Lfg1:/usr/src/linux-2.6.22/Drivers/USB/storage #Cat makefile
#
# Ma
In 1991, one introduced the concept of pipelines in Linux and used pipelines in many places, such as file systems and device drivers. So we can see that there are various pipelines in Linux. But the same thing is that all pipelines are used to transmit things, but some pipelines transmit real material while some pipelines transmit data.
The pipe we see in the USB code is used for data transmission and communication. Communication is from both parties
1-2 is omited, for more detail please referWww.usb.org.
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3 layout guidelines
3.1 General Routing and placementUse the following general routing and placement guidelines when laying out a new design. TheseGuidelines will help to minimize signal quality and EMI problems. The high speed USB validation effortsFocused on a four-layer motherboard where the first layer is a signal layer, the second layer is power,Third layer is ground and the fourth i
Recently installed in the old machine on the CentOS system, with the Chinese cabbage or ultraiso after making the system disk, the start booting from USB device and boot failed, has been very depressed , thought to be the cause of the system. It's not working on the Internet to say that the Syslinux file is modified or replaced. The final discovery is the format of the U-boot, which does not match the format of the BIOS boot
Recently in the use of STM32 USB module to develop a project, it is very simple, the result of a fast two days to the USB packet buffer access to do a little summary here.
The STM32 USB module packet buffer has 512B, but in the STM32 reference manual memory image shows that 0x40006000-0x400063ff, a whole lot of 512B, how can this, but also in the attempt to progr
Small series very do not like other people's USB stick to my computer, because the friends they always have some strange software and other things, and the U disk insert always let me feel some files on the computer is not safe! Bean System Small Series today share this method can be set in the Win7 system only read the development of USB flash drive, Other U disk computers are not read! Let's take a look a
With USB3.0 control chip motherboard, although has become the mainstream of the market, but for most users still use USB2.0, USB2.0 file transfer speed also seems to be unable to meet their requirements. In fact, now USB2.0 speed there is room for improvement, we can use the speed-increasing patch to explore the potential of USB2.0.
USB 2.0 Why not reach the 60mb/s?
We all know that the theoretical bandwidth of
Android USB Connections Explained:mtp, PTP, and USB Mass StorageOlder Android devices support USB mass storage for transferring files back and forth with a computer. Modern Android devices use the MTP or PTP protocols-you can choose which one prefer.To select a USB connection protocol, open the Settings app, tap Storag
Recently, as a result of the business relationship, we need to install an HP Server that was originally installed with win2003 into a red hat linux6.1.
I thought it was a simple task. I ran into the data center with a CD. As a result, I was stunned. No one of the three DVDs was available, and all of them showed medium damage. (Mei's) it's troublesome now.
Think that windows can be installed from a USB flash drive, so linux should be fine.
The preparat
In 1991, one introduced the concept of pipelines in Linux and used pipelines in many places, such as file systems and device drivers. So we can see that there are various pipelines in Linux. But the same thing is that all pipelines are used to transmit things, but some pipelines transmit real material while some pipelines transmit data.
The pipe we see in the USB code is used for data transmission and communication. Communication is from both parties,
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android:4.4.4
First, the problem analysisWhen the USB printer is plugged into an Android device, there is no printer node (/DEV/USB/LP0) generated in the System/dev directory.The first reaction is to check the printer device and access the Ubuntu-equipped PC, normal: /dev/
The usb_stor_bulk_transfer_sglist () function is confusing. We have mentioned that sglist is used to improve transmission efficiency. As we know, SG aims to transmit a bunch of discontinuous buffers in one DMA Operation. In fact, this is not the case in the story of USB. However, if you don't care about the behavior in the USB core, it doesn't matter.
Row 3 and row 3 do not pass data if you exit or break th
USB device is a collection of ports, interfaces, configurations, USB protocol is a variety of USB descriptors to characterize the function of USB devices. The computer uses these descriptors to obtain the functionality of the USB device.USB descriptors include:
Install ubuntu on a USB flash drive and start Linux from the USB flash drive.
If we install the Linux system directly on our hard disk, the GRUB of Linux will overwrite the boot guide of window. It is not convenient to carry. So I want to install a ubuntu system on a USB flash drive, which can be started on any computer.
Preparations:
A 32g
First, verify the USB device is normal
: If the laptop is plugged into the USB device itself, there may be a problem with USB can not use the phenomenon.
Verification Method:Method One:Plug the USB device into another computer to see if the computer is available. If this device is not available on other computers, th
Disable usb in Domain Policy and usb in Domain Policy
Documents and templates can be downloaded in http://pan.baidu.com/s/1qYTcjTy
Pro_usb_users.adm this template can be disabled to the specified drive letter, for user policy
Pro_usb_computers.adm this template is intended for computers. Generally, it is enough.
You can start from three aspects
In fact, the adm configuration file seems to have modified th
Rome was not built in one day. Before making the USB flash drive work, we actually made a lot of preparations for the driver.
We continue to follow our feelings. storage_probe (), 972 to 975 rows, and a series of functions named init _ * are called at the moment. Here some lock mechanisms and wait mechanisms are involved, however, it is only initialization, but it is ignored for the time being. It will be explained later, but remember that each row o
Recently, as a result of the business relationship, we need to install an HP server that was originally installed with win2003 into a red hat linux61. I thought it was a simple task.
Recently, as a result of the business relationship, we need to install an HP server that was originally installed with win2003 into a red hat linux6.1.
I thought it was a simple task. I ran into the data center with a CD. as a result, I was stunned. no one of the three DVDs was available, and all of them showed medi
Http://www.easyuefi.com/wintousb/index-cn.html Tools to use Wintousb attached: Win8 can be used Windows to Go Easily install WINDOWS/WINPE to a USB removable hard disk or USB flash drive!Wintousb is a free application software. It installs the Windows operating system from an ISO disc image or CD/DVD drive to a USB removable hard drive or
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