How to record data on an SD card. Arduino: Recording and Reading Micro-SD Maps
memory Does not be dangerous for your PC, check its contents for viruses. To do this, insert the USB flash drive and open the My Computer folder. Right-click on the defined device and select "Scan". If the antivirus does not detect on the carrier of malicious programs, you can open the partition.To record information on map memory, Find the necessary files and highlight them. Click on the highlighted area with the right mouse button and select "Copy". Open the Maps section memory and click on it right mouse button. By selecting "Paste", click on it and wait for the file transfer to the device.
After all the files are transmitted, remove map memory in the following way. On the taskbar, right-click on the USB port icon and select "Safe Removing Device". By clicking on this option, wait for the display of the notification window that it can be extracted from. Just pull out after that map memory. If you just pull the device from the port, you can damage files stored on it and documents.
The Arduino family boards have several types of memory. First, it is a static RAM (operational storage unit), which is used to store variables during the program execution. Secondly, it is a flash memory in which the sketches written by you are stored. And thirdly, it is EEPROM, which can be used for constant storage of information. The first type of memory is energy-dependent, it loses all the information after rebooting Arduino. The second two types of memory stores information until it is overwritten new, even after turning off the power. The latest memory type - EEPROM - allows you to write data, store them and read if necessary. We will consider this memory now.
You will need
- - Arduino;
- - a computer.
Instruction
EEPROM Means Electrically Erasable Programmable Read-Only Memory, i.e. Electrically erasable reprogrammed constant storage device. Data in this memory can be stored dozens of years after power out. The number of overwriting cycles is about a few million times.
The amount of memory EEPROM in Arduino is quite limited: for boards based on the ATMEGA328 microcontroller (for example, Arduino Uno and Nano), the amount of memory is 1 KB, for boards on ATMEGA168 and ATMEGA8 - 512 bytes, on ATmega2560 and ATMEGA1280 - 4 KB.
For work with EEPROM for Arduino, a special library is written, which is included in Arduino IDE by default. The library contains the following features.
read (Address) - reads 1 byte from EEPROM; Address - address from where data is read (cell starting from 0);
write (Address, Value) - records the value of Value (1 byte, number from 0 to 255) to Address;
update (Address, Value) - replaces the value of Value to Address, if its old content differs from the new;
get (Address, Data) - reads Data data of the specified type from memory to Address;
pUT (Address, Data) - writes the Data data of the specified type to memory at the address Address;
EEPROM. - Allows you to use the EEPROM identifier as an array to record data into memory and read them from memory.
To use the library in the Sketch, we connect its directive #Include Eeprom.h..
Let's write two integers to the EEPROM memory, and then read them from EEPROM and remove to the serial port.
With numbers from 0 to 255 no problems, they occupy exactly 1 byte of memory and using the function EEPROM.WRITE () Write to the desired cell.
If the number is greater than 255, then using operators highByte () and lOWBYTE () It must be divided into bytes and record each byte in its cell. The maximum number is 65536 (or 2 ^ 16).
See, the monitor of the serial port into cell 0 simply outputs a number less than 255. In cells 1 and 2, a large number of 789 is stored. In this case, the cell 1 stores the overflow multiplier, and the cell 2 is the missing number 21 (i.e. 789 \u003d 3 * 256 + 21). To re-"collect" a large number, disassembled to bytes, there is a function word (): int val \u003d Word (Hi, Low), where Hi and Low are the values \u200b\u200bof senior and younger bytes.
In all other cells that were never recorded by us, the numbers 255 are stored.
To write floating semicolons and strings you need to use the method EEPROM.PUT (), and for reading - EEPROM.GET ().
In the procedure setup () First, write down the floating point f. Then shifts on the number of memory cells, which occupies the type of Float, and write the CHAR character string of 20 cells.
In the procedure loop () We will read all the memory cells and try to decrypt them first as the type "float", and then as the type "char", and output the result in the serial port.
It can be seen that the value in cells from 0 to 3 correctly determined as a floating point number, and starting with the 4th - as a string.
Appearing values ovf. (overflow) and nan. (not number) suggest that the number cannot be correctly transformed into a floating point number. If you know exactly what type of data which cells are occupying, you will not have problems.
Very convenient opportunity - access to memory cells as an array elements EEPROM.. In this sketch in the procedure setup () We first write data to the first 4 bytes, and in the procedure loop () We will read the data from all cells every minute and withdraw them to the serial port.
Video on the topic
Tip 3: How to write down and read flash memory using Arduino
In the article, we will look at how to write to flash memory and read from flash memory using Arduino on the example of the microcircuit 25L8005.
You will need
- - Flash memory microcircuit with SPI interface support;
- - memory adapter or zero-gain panel (Zif panel);
- - Arduino;
- - a computer;
- - Connecting wires.
Instruction
First we need to make so that we can easily connect to the chip. To do this, you can use either a special adapter to which the chip will have to be soldered, or (which is preferable) to use a zero gain panel (so-called. ZIF panel).
Now gather electrical circuit Connecting flash memory microcircuits to Arduino. We will use the SPI interface to program memory, so connect to standard outputs:
- CS - digital pin 10,
- MOSI - digital pin 11,
- MISO - digital pin 12,
- SCK - digital pin 13.
There are many different types Data media based on the so-called flash memory. We use conventional flash drives to transfer files to each other, Micro-SD cards to increase the free space in smartphones, even instead of the old good hard disk in modern laptops, use SSD media - the same flash memory. Flash memory does not have moving parts, unlike old diskettes and newer hard drives. The speed of reading and writing such a memory is higher than that of all previous media, and the power consumption is the opposite below. In other words, if we want to store some data in our electronic devices and robots, it will be rationally to use precisely flash memory. Why do you need a memory card? For example, in order to record data from various sensors of our device. In addition to the sensor readings themselves, it is rational to record the time of the removal of these readings - this is called journaling. Thus, connecting the temperature, humidity and pressure sensors, as well as the clock of real time and the memory card, we can make a real weather station! We will examine how exactly the memory card connects to Arduino and how it is recorded and reading.
1. Connecting the MICRO-SD card module to Arduino
In this lesson, we will read and record data on a Micro-SD card. In terms of connecting to Arduino, the Micro-SD module is no different from the module for ordinary SD cards. The module is connected to Arduino on the SPI bus, which means you need to connect the contacts already familiar to other lessons in the standard order:| Module Micro-SD cards | GND. | VCC. | CS. | MOSI. | MISO. | SCK. |
| Arduino Uan | GND. | + 5V. | 4 | 11 | 12 | 13 |
Appearance layout
2. Micro-SD card reader
To check the operation of the device, write a simple program that will only read the service information from the card: the type of map, the type of file system, the size of the first partition and the list of files on it. #Include.
If such information appeared, it means that everything is in order with the card and module. You can proceed to further work. 3. The program for writing data on a Micro-SD card
Now let's try to create a new file on the map and write there a simple phrase "Hello from Robotclass". #Include.4. Data reading program with micro-SD card
Finally, read the TEST.TXT file and bring text from it to the COM port. #Include.Conclusion
In the next lesson, we will try to add real-time clock and temperature sensor to the scheme. Leaving such a device for a whole day, we will eventually build a daily temperature schedule.For most people, MicroSD is only a form factor, but in fact it is not. You can easily insert any microSD card into a standard slot, but not every one of them will work, as cards differ in many signs.
Format
There are only three different SD formats available in two form factor (SD and MicroSD):
- SD (MicroSd.) - drives with a volume of up to 2 GB, work with any equipment;
- SDHC (Microsdhc.) - drives from 2 to 32 GB, work on devices with support for SDHC and SDXC;
- SDXC (MicroSDXC.) - drives from 32 GB to 2 TB (currently a maximum of 512 GB), work only on devices with SDXC support.
As you can see, they have no backward compatibility. The new format memory cards will not work on the old equipment.
Volume
MicroSDXC supported by the manufacturer does not mean support for the cards of this format with any volume and depends on the specific device. For example, HTC One M9 works with MicroSDXC, but officially supports only cards up to 128 GB inclusive.
With the volume of drives, another important point is associated. All MicroSDXC cards use the default EXFAT file system. Windows supports it for more than 10 years, in OS X it appeared from version 10.6.5 (Snow Leopard), in Linux-distributions EXFAT support is implemented, but "from the box" works far from everywhere.
High Speed \u200b\u200bUHS Interface
To the Map Logo with UHS support, I or II are added depending on the version. SDHC and SDXC formats maps can support Ultra High Speed \u200b\u200binterface, which, with hardware support on the device, provides higher speeds (UHS-I to 104 MB / s and UHS-II to 312 MB / s). UHS is backward compatible with earlier interfaces and can work with non-supporting devices, but at a standard speed (up to 25 MB / s).
2. Speed
Luca Lorenzelli / Shutterstock.com The classification of the speed of recording and reading microSD cards is as complex as their formats and compatibility. Specifications allow you to describe the speed of card by four ways, and because manufacturers use them all, a big confusion occurs.
Speed \u200b\u200bclass
Macricing class speed for ordinary maps represents a figure inscribed in the Latin letter C Speed \u200b\u200bClass (Speed \u200b\u200bClass) is tied to the minimum recording speed to the memory card in megabytes per second. There are four of them four:
- Class 2. - from 2 MB / s;
- Class 4. - from 4 MB / s;
- Class 6. - from 6 MB / s;
- Class 10. - From 10 MB / s.
By analogy with the labeling of ordinary cards, the UHS card speed class fits into the Latin letter U In maps working on a high-speed UHS bus, so far only two class of speed:
- Class 1 (U1) - from 10 MB / s;
- Class 3 (U3) - from 30 MB / s.
Since the minimum recording value is used in the rating of the speed class, then theoretically, the second-class card may well be faster than the fourth card. Although, if it is so, the manufacturer will most likely prefer to more explicitly specify this fact.
Maximum speed
The speed class is quite enough to compare cards when choosing, but some manufacturers in addition to it are used in the description maximum speed in MB / s, and more often not even the recording speed (which is always lower), but reading speed.
Usually these are the results of synthetic tests in ideal conditions that are unattainable with normal use. In practice, speed depends on many factors, therefore should not be focused on this characteristic.
Multimitator
Another classification option is a speed multiplier similar to that that was used to specify the read speed and write optical disks. Total more than ten, from 6x to 633x.
The factor of 1x is equal to 150 kb / s, that is, the protozoa 6x-cards the speed is 900 kb / s. The fastest card multiplier may be 633x, which is 95 MB / s.
3. Tasks
StepanPopov / Shutterstock.com. Correctly choose a map taking into account specific tasks. The biggest and fastest is not always the best. With certain use scenarios, the volume and speed may be redundant.
When buying a card for a smartphone, the volume plays a big role than speed. The advantages of the large drive are obvious, but the advantages of high transmission rate on the smartphone are practically not almost not felt, since large volume files are rarely recorded and read (unless you do not have a smartphone with support for 4K video).
Cameras, shooting HD and 4K-video, is quite another thing: speed is equally important, and the volume. For 4K video, camera manufacturers recommend using UHS U3 cards, for HD - regular Class 10 or at least Class 6.
For photos, many professionals prefer to enjoy multiple smaller cards to minimize the risk of losing all pictures in force majeure circumstances. That up to speed, it all depends on the photo format. If you are removed in RAW, it makes sense to spend on Microsdhc or MicroSDXC class UHS U1 and U3 - in this case they will reveal themselves to fully.
4. Fake
jcjgphotography / shutterstock.com. No matter how banal it sounds, but to buy a fake under the guise of original cards is now simpler simple. A few years ago, SanDisk stated that a third of the SanDisk memory cards in the market is counterfeit. It is unlikely that the situation has changed much since that time.
To avoid disappointment when buying, it is enough to be guided by common sense. Recompaning from buying from sellers who do not deserve confidence, and beware of the proposals of the "original" cards, the price of which is significantly lower than the official.
The attackers learned to fake the packaging so well that sometimes it is very difficult to distinguish from the original. With full confidence, judge the authenticity of a particular card, only after checking using special utilities:
- H2Testw.- for Windows;
If you have already encountered the loss of important data because of the breakdown of the memory card for one reason or another, when it comes to choosing, you will most likely prefer more dear map of the famous brand than the available "Nunney".
In addition to the greater reliability and preservation of your data, with the brand card you will get high speed and guarantee (in some cases even lifelong).
Now you know about SD cards All you need. As you can see, there are many questions that you have to answer before buying a map. Perhaps, best idea will have different cards for various needs. So you can use all the advantages of the equipment and do not subject your budget extension.
Attempting to save new information on micro CD will fail if it is worth writing protection. The reasons for the appearance of an access message may be different. You can remove MicroSD protection with several methods - software and physical. Consider the most relevant.
Unlocking MicroSd.
Place the memory card on a flat surface or on the palm it so that the label is on top. The layer side of the Card Enclosure Top Find a small lock switch lever - Lock button. "Locker" serves to protect information from accidental erasing. The lever can be flat and only slightly perform from the housing, be white or silver. This switch is missing directly on MicroSD. Insert the card into the adapter and locate the Lock switch on the adapter itself. Move it until you stop in the opposite direction.
After translating the LOCK lever to the cancellation status status status, the recording error notification window is repeatedly caused by the translation back to the protection position. This is due to the loosening of the switch, when entering a memory card to the card reader, it shifts and turns on the memory lock. Lock it with a piece of gum, cardboard or remove at all.
Avoid automatic recording lock on MicroSD you can remove its contact with the LOCK button on the adapter case. On the left side of the micro flash drive, find a small gauge, throw it with plastic or creep the scotch. Perform the soldering is very neat. The variant with chest is easier, but it can be cling when entering the card into the adapter.
Change disk properties
If the memory card protection does not allow you to copy information to another disk, and it is necessary to save it, then try to remove the protection as follows. Attach the micro CD to the computer, find it in the list of devices and click on it right-click. In the menu, select the "Properties" string, then the "Access" tab. The next window has "Extended Setup", open it and check the "Open Share" string, confirm the settings - OK.
MicroSD memory card formatting
Sometimes it is recommended to format it to remove protection from the memory card if the "locker" is missing or did not help. Important information Save to another disk, because It will be completely removed. Software can be removed the lock from writing to the card using Windows.
Install the MicroSD memory card on a personal computer through a special adapter directly or through the card reader. On modern laptops, such a connector is already provided, it is usually indicated by the "Map" icon and looks like a narrow gap. Operating system Recognizes disk, and its name will be displayed in the list of computer devices.
Right-click on the CD disk icon and select "Format ..." in the launched menu. File System Set the one that your device supports, usually - NTFS. Click "Start". All information from the disk is now deleted, and the protection status is removed.
Change file system
When recording a file memory card with a volume of more than 4 GB, the error notification can occur due to the limitations of the file system. If the memory card is formatted with the FAT32 system, the file size is one of its restrictions for data recording. You should change the file system to NTFS, as described in 3 points.
MicroSD software
Reset protection from writing on a disk can be software, without deleting information. To do this, there are various scripts and utilities, for example - reset.zip. Downloading software from the network, you should be careful - it may contain viruses. It is better to take advantage of the protection of proven applications. Low-level disk formatting The Hard Disk Low Level Format Tool is erases all the data, but it will help to restore even hopeless flash drives that have not been formatted by internal uses of Windows.
Removing MicroSD protection through a mobile device
Modern Mobile Devices: Players, PDAs, Phones, Cameras have a MicroSD formatting function. Try to find this option through the settings and format the USB flash drive directly on this device. Memory protection could be programmatically installed in the device to ensure data confidentiality. You can also withdraw protection in the settings. All varieties of electronic devices have their own characteristics, so in case of difficulties, read the instruction of the gadget or get an explanation in the service center at a specialist.
Use with MicroSD card only "native" adapter. With another adapter, even if you managed to format on the phone, write information to the disk, most likely it will not work.
Modern mobile devices And in addition to the main memory of a small amount of small volume, the amount of which can be solved at times to exceed the scope of the main memory. For an unrecorded person, this is a novelty, which generates a lot of issues regarding the use of a memory card. Memory cards are of different sizes, but they have the same work. So all the tips that will be listed below are suitable for any type of device.
The first difficulty arises with how to write data to the memory card. If work is done on a laptop, it has a special slot where the map is inserted. But this slot is made under a large map. If the card is small, then there are adapters to which it is inserted, and the work is made as with a large one. For a computer, there are adapters that are connected as drives. In the system, the memory card is defined as a removable disk, so the recording is made as if it is a flash drive. The only difficulty may be the extraction of the card from the device.
Therefore, the next question concerns how to pull the memory card. Devices that support memory cards use high-spring holders. On the body of the phone or the camera there is a memory card socket, as a rule, closed with a rubber or plastic lid. To retrieve, you need to open it and lightly click on the card before clicking. After that, it will come out of the nest and can be pulled out with his fingers. From the card reader, the extraction scheme is the same. If you need to insert a map back, you must press it into the slot until it clicks.
In addition, difficulties are often associated with how to clear the memory card. If you need to clean it not completely, you need to go to it and delete unnecessary files one by one. If complete cleaning is required, then you need to format it. To do this, you need to right-click on the device and select Formatting item. In the window that appears, you need to select the necessary settings and click the Start button, followed by confirming the operation. In addition, all these actions are available directly from the device to which the memory card corresponds to.
Very often ask questions about how to unlock the camera's memory card. If the SD format is, it has a jumper on the left edge, which, with an inactive installation of the card, switches to the lock position. This jumper must be put in the upper position and gently insert into the camera. You can only unlock cards only in the service center, then all the information on it will be saved. If the information on the card is not particularly important, you can safely produce its formatting.
Often users forget passwords and questions arise as to how to remove the password of the memory card. If it is a smartphone, then you need to go to system files and find a file with the MMCCSTORE name. This file must be renamed with the TXT resolution and open it. Among the various incomprehensible characters will slip the Arabic numbers. Their combination is password. The second way is the simple formatting of the memory card, resulting in a password. The second way is easier, but is suitable only if the information on the card is not important.
