The principle of operation USB flash drive. Choose a flash drive. The main characteristics of USB flash drives. Sick before death sweated? This is bad

We used to use the benefits of civilization and recently they do not even notice them. But many are wondering how one or another mechanism works. This article is written for inquisitive people who are wondering how the flash drive works? By restoring flash drives can.

Memory cells are used to store information. One cell is able to keep in itself only one bit. This bit records the binary code element 0 or 1.

In one flash drive there are billions of cells that are ready to memorize information for you. One byte is obtained from eight bits. So a storage device for one gigabyte consists of 8,589,934,592 cell cells, and this article is suitable for approximately 20,000 cells.

Read more about memory cells

Memory cells are transistors. The transistor has two semiconductors N-type, they are on his sides. These semiconductors have many free electrons. When the movement of these particles passes the current.

In the middle of the N-type semiconductors placed the P-type semiconductor, which is characterized by a disadvantage of electrons. For it, the current is transferred through holes in which electrons lacks.

Because of the distinguished type of conducting the conductivity of these semi, the current does not have the opportunity to go between them.

The transistor design provides for the presence of a control shutter, which is located above the P-semiconductor. It is an electrode and voltage is supplied to it. When the positive voltage is submitted, it moves the holes of the p-semiconductor and attracts particles. This is justified by attracting opposite charges.

This results in the so-called N-transition. It is needed to transition of electricity from one n-semiconductor to another, with the result that the transistor skips current.

The control shutter has a separation with a p-semiconductor, which is called a floating shutter (polycrystalline silicon plate). With a negative charge, the current plate will not be carried out by the transistor, independent of the charge of the control shutter, which may interfere with its work in the future.

Reading data

The process of reading information from the flash drive is as follows. The control shutter is given voltage. This is necessary to determine the zero or units that are in this memory cell. The combination of zeros and units gives a presentation of the machine that reads information about the encoded characters.

With an excess of electrons in the control shutter, the current does not go. This indicates a unit.

With the lack of electrons in the control shutter, the current goes. This indicates zero.

Data record

To record information, it is necessary to fill the floating shutter with electrons. But this is a difficult task due to a dielectric layer, which surrounds it and does not allow to go through.

Electrons in a floating cell are placed in the supply of a positive charge, above what is supplied when reading, in which they jump, passing the dielectric layer.

When erasing information on the floating shutter, a negative voltage is served, and electrons fall from the floating shutter.

This is how that little thing works, which facilitates the exchange of information.

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Hello my friends. Today we will not consider some schemes of certain designs, the theme for today is the so-called homemade flash drive. Some of course may not believe that it is possible at home, and do it right, because it is quite difficult and to make at home without special equipment is practically impossible. But smart people have long come up with a memory card for mobile phones. In stores it is easy to find an adapter with which you can connect a memory card via USB port. Such an adapter costs only 2 dollars.

The device works very simply - just need to put a memory card to a certain place on the adapter, and the adapter itself is made in the form of a Plug Yusb that only needs to be connected to the USB port of PC. For our homemade flash drive, you need to have exactly such an adapter with a memory card from mobile phone And another plug or the corresponding plastic case for YUSB.

Then the adapter is placed in the plug casing and close the lid and look at what we did.

Now it looks like a cropped yusb plug, but no one will even suspect that there is a memory drive! Now it came to the queue schematics. There are 4 wires there, we remove the small part of the insulation from the wires and we ride them. Next, take a couple of new details (it is better to take spoiled, but in order to be like new ones) and launch them to each other. There is no specific scheme, solder what you want, the design should simply look like a scheme, of course it will not work! You can use condensers, resistors, polar and non-polar capacitors and a pair of transistors, as you know, some flash drives have a back built-in led indicator, You can get a simulator of such an indicator so that our homemade flash drive looks plausible and did not cause doubts.

To do this, the article attached unpacking Yusb socket and plug, on the side channels is supplied to the power to connect to our wires, then collect the simplest scheme Flashing for one LED, in which case we still have two free wires to which you can attach in advance made<блеф> memory storage circuit. So, let's sum up - we have a fairly interesting design, when connected to a USB port of the computer, the LED will flash and in foreign one will cause the feeling that the flash drive is connected, but they will survive more when the computer will notify that the memory drive is connected to it! Yes, everyone will believe that you are a genius and ask the scheme of such the simplest wonder of the flash drive. Try to make the scheme for connecting parts as confusing as possible so that even the master on suspects what is there. Well, that's all, such interesting things can be seen in further articles, goodbye friends - Arthur Kasyan (Aka).

The essence of the problem

After power failure, the appeal to the flash drive becomes impossible because the computer either does not respond at all to its connection, or the message "USB device is unidentified" is displayed. This type of damage is more prone to USB flash drives, since they are powered directly from the USB port and use their own converters to power the internal circuits. SD, MicroSD, CF cards are usually used in photo video technique. And when connecting to a computer, it is not directly powered by it, since intermediate devices are applied to connecting them - Card readers.

Causes of occurrence

• Invalid connection of additional USB connections to the motherboard
• Fault motherboard or power supply that led to an increase in voltage on USB connectors.
• Defective uSB extension cords and USB hubs with low-quality power supplies
• Spontaneous failure of flash drive elements

Symptoms

• Full absence of a system reaction to connect flash drive
• The appearance of the message "USB device is unidentified"
• Message about exceeding the allowable current consumed from USB connector
• The smell of burned from the flash drive.

Impact on user files

The impact of this malfunction on user information depends on the degree of damage. If you fail only the flash drive circuit, it does not affect the user data and they are completely restored. If the controller flashes, it is necessary to get a memory and read it on the NAND-reader. In this case, the quality of recovery is usually good. But if the flash drive memory chips are punched directly, then in this case it is usually impossible to recover data.

Diagnostic methods

Electric damage to flash drives are diagnosed in the same way as in any electronic device. The burnt elements with traces of thermal damage can be seen immediately. The rest is checked by appliances. Protection elements are checked (if any). Checked fed on the voltage scheme. Modern production goes along the way to increase integration and maximum reduction in the number individual elements In devices, as well as on the way of improving energy efficiency, linear voltage stabilization schemes are replaced by pulse, with high efficiency. Let's see how the circuit circuit circuits flushe with time changed.
In fig. 2 shows other two flash drives, on completely different controllers. In general, they have what they contain the minimum of active components (microcircuits) are only controllers and memory chips, the remaining elements are passive - resistors, condensers. Those. Although a little, but the cost of production is reduced. On the top flash drive, the controller is U1, on the bottom - U4. Both the power stabilizer is embedded in the controller.

Well, the most modern option.

This is a USB 3.0 USB flash drive with an IS916 controller, it has a built-in voltage converter for its own power supply, and the flash memory microcircuits are applied separately pulse converter U4, which reduces overall energy consumption and heating compared with linear stabilizers.

Methods of recovery

In the first embodiment, as in Fig. 1 The entire blow takes on the stabilizer U2, the rest, as a rule, remains a whole. Therefore, it is enough to supply the power of 3.3V at the desired point of the circuit, connect a USB flash drive and read the data. The only thing that spoils this idyllic picture is that such flash drives are no longer produced. The photo shows the TRANSCEND JETFLASH 512MB flash drive.

In the second variant in fig. 2, where the power stabilizer is built into the controller, it is impossible to do so. Here it would be possible to replace the controller, but it is very difficult to find. T. K. They, even within the same model, are distinguished by firmware, depending on the time of release and the flash memory used by the chip, which together generates many combinations. The only option to restore such a flash drive is dropping and subtract flash microchips.

How does a flash drive work?

Flashki, or USB flash drives - these are storage devices, record and reading information. Thanks to them we can wear huge data arrays in your pocket: photo galleries, music concerts, price lists, cards, presentations, etc. But how it becomes possible? Let's talk in this article about how the flash drive works.

How the flash drive works: device

The simplest flash drive is calculated at least 10,000 rewriting cycles. But the best instances can withstand 100,000 cycles. If you do not overwrite information several times on the day, this resource could have been enough for an unlimited time. However, data is usually stored no more than 10 years. As a rule, during this time, people manage to replace the drive several times to a more modern device.

And nevertheless, sometimes it happens that the flash card suddenly fails: when connecting the computer "does not find out" it, reporting that this is an "unknown device". To understand, you need to see its device at least in general terms.

Inside the small flash drive placed several blocks:

• microcontroller;
• microcircuit (chip) flash memory;
• the source of clock frequency is a quartz resonator;
• light-emitting diode;
• record protection switch.

The main part is a memory matrix. It consists of a variety of cells in which information is recorded. One cell is 1 bits of information. The computer uses binary logic: operates exclusively with zeros and units. There is a voltage in the cell - one, no voltage - zero. In order to record one sign - letter, digit, space, etc. - You need 8 bits or 8 cells. 8 bits are called byte. Each flash drive can be stored millions of information byte.

The main advantage of the memory matrix is \u200b\u200bthat the data is not lost in the absence of supply voltage, i.e. It is non-volatile.

Manages memory cells controller, this is the drive control unit. The controller when connected, drives the current over all cells, checks where it is recorded 0, and where 1. The signal from the computer comes to it through the connector.

In accordance with this signal, the control unit refers to those cells that are specified in the query, and allows data written in these cells to enter the computer. Or vice versa, the controller reads data from the computer and sends them to the selected cells.

For the normal functioning of the flash drive is needed clock frequencywhich is generated by a quartz resonator. It is he asks the speed of the flash drive.

What to do to the flash drive worked without failures

Never pull out the flash drive from the working computer. Previously need to turn it off. In these cases, the computer writes that the memory device can be deleted. This means that from the computer to the controller received a shutdown signal, and the corresponding service information was written to the control unit.

If you pull out the flash drive without shutting down, the service information can be knocked in the controller, and then it will no longer be able to connect to the reader. The same can occur with sharp voltage drops.

The controller is the most vulnerable part of the flash drive. A high-quality memory matrix and a quartz generator almost never fail. To destroy them, you need to either break the USB device, or to file very high voltage. But you can crossed the connector if you treat it inaccurately.

Flash drive is a storage device using flash memory. Flash memory is non-volatile. It can be electrically erased and reprogrammed.

Thus, this type of electrically washed programmable permanent memory, referred to as EEPROM (Electrically Erasable Programmable Read-Only Memory) - electrically erasable reprogrammed ROM. This type of memory can be emitted and filled with data to a million times. Flash discs are similar to conventional hard drives and can replace them. Flash memory is used for easy and quick storage and information transfer.

About flash memory

Flash discs are often used in products that work at low power and those that may have to work in harsh conditions. Flash memory is non-volatile, and therefore flash drives should not be backed by the battery. Flash memory solid-state. This means that there is nothing mechanical in it. All purely electronic. Flash memory has a grid of columns and rows, each cell has two transistors at each intersection point in the grid. The thin oxide layer separates the transistors in each pair. One transistor in a pair is called a floating shutter, and the other is known as a regulating shutter. Floating shutter can hold electric charge. This charge consists in electrical insulation of the oxide layer separating it from the gate of the control. Thus, any electrons placed on a floating shutter remain on it. This makes non-volatile flash memory. The work of flash memory is precisely in adding and removing electrons from floating shutters.

How does a flash drive work?

It must be inserted into the USB port on the computer. Today's operating systems can detect flash drives and install required drivers Alone. Once the device is detected, it can be used to store data. The flash drive can be extracted from the computer only after its work will be over. The system will prompt when it can be safely removed, after which it can be removed physically.

Flash drive consists of pCB and covered in a plastic or rubber casing that makes it durable. USB connector, which sticks out the outside closes with a removable lid. Most flash drives use uSB connection Type A, it makes them compatible with standard computer connectors. Therefore, they can be connected directly to the port on your computer.

Flash drives do not require any additional devices drivers. When the flash drive is connected to the computer on which the block logical unit operating system is installed, while abstraction from the details of the implementation of complex flash memory devices and the operating system can use any file system or addressing the system blocks. In short, the operating system considers it as hDD. When connecting a flash drive enters the emulation mode, which means that it emulates the work hard disk further. This makes the transmission of data between the flash drive and the computer is much easier.

Flash drives are used in managing operating systems in order to turn personal computers In the network of electrical appliances. In such cases, they contain operating system And used to load the system. Flash discs have an advantage over other devices due to their low power consumption and low levels of failures. In addition, flash drives have a small portable size. They enable rapid data transfer with less difficulties. Basically, they are plug and-play devices. They do not require any special preparation on your part to be able to use them. They have a big memory store, the amount of memory is greater than that of a floppy disk or CD.

During the first years of their evolution, flash drives could not withstand, too many erasure cycles. It made early flash drives unsuitable for data that needed frequent updates. To fill this space, manufacturers have developed a leveling method that physically distributes data on all memory cells. Modern flash drives can withstand up to a million cycles.

USB Flash Drives

USB Flash drive is fashionable today in computer technologies. This is a flash memory or a NAND-type memory storage device. The main components of the flash drive include a USB type A connector, a storage controller, a NAND flash memory chip and a quartz generator. The USB connector acts as an interface between the device and the computer. The storage controller consists of a tiny RISC processor. It also has some memory on the microcircuit (it can be ROM and RAM). Flash memory chip makes actual data storage work. The quartz generator generates clock signals and manages the data output from the device. LEDs acting as indicators are protected from recording and switch some other components that can be part of the flash drives.

Usage Flash Drive

• Connect the flash drive to the computer.
• The computer will indicate you that he discovered an external device.
• The operating system will perceive it as any other hard disk. No special drivers are needed by the device. No specific file System not required.
• Go to the "My Computer" menu and you will see a flash drive among other disks.
• You can open it like any other hard drive.

Advantages of flash drives

• They are light and portable.
• They are reliable. They are resistant to scratches and are not affected by magnetic fields.
• Flash memory is non-volatile.
• They are "plug-and-play" devices, so they are easy to use.
• The computer perceives them as any other hard disk, thereby making the transmission of data easy.

Disadvantages of Flash Drives

• They are small. So they can be easily lost.
• Frequent use leads to wear, especially at the point of their connections to the computer.
• There is a limit on the number of recording cycles and erasing, which they can withstand.
• Using a flash drive on various computers makes it susceptible to infections. The virus on the disk can destroy the data or make them unreadable.

Modern flash drives are equipped with security measures, such as encryption or even biometric data. They are equipped with a protective casing that makes them reliable. Although the number of erasing and recording cycles may be limited. They have an additional advantage, because they have capacity, speed, portability and low power consumption. It is clear that flavors of flash drives are negligible compared to the simplicity of use they offer. Flash drives today are among the most popular storage devices. They can perform program downloads, you can store important documents, projects and homework, they can store music, movies and images.