arduino lcd module sd card reader quotation

The Arduino TFT screen is a backlit LCD screen with headers. You can draw text, images, and shapes to the screen with the TFT library. There is an onboard micro-SD card slot on the back of the screen that can, among other things, store bitmap images for the screen to display.

The screen"s headers are designed to fit into the socket on the front of the Arduino Esplora, but it is compatible with any AVR-based Arduino (Uno, Leonardo, etc) or with the Arduino Due. The TFT library interfaces with the screen"s controller through SPI when using the TFT library.

Storing data is one of the most important parts of every project. There are several ways to store data according to the data type and size. SD and micro SD cards are one of the most practical ones among the storage devices, which are used in devices such as mobile phones, minicomputers and etc.

The SD and micro SD card modules allow you to communicate with the memory card and write or read the information on them. The module interfaces in the SPI protocol.

NoteThese modules can not handle high-capacity memory cards. Usually, the maximum identifiable capacity of these modules is 2GB for SD cards, and 16GB for micro SD cards.

What’s Next?Create an entry/exit control device. Using the RFID module and Arduino, save entrance and exit time for several persons on the memory card. (Consider an RFID card for each person)

The Arduino TFT library extends the Adafruit GFX, and Adafruit ST7735 libraries that it is based on. The GFX library is responsible for the drawing routines, while the ST7735 library is specific to the screen on the Arduino screen. The Arduino specific additions were designed to work as similarly to the Processing API as possible.

The TFT library relies on the SPI library, which must be included in any sketch that uses the scree. If you wish to use the SD card, you need to include the SD library as well.

This microSD (uSD) breakout board makes connecting a microSD card to your project a cinch. It functions using the "SD" interface (quad-SPI) or standard 4-wire SPI. The uSD card pins are broken out to a 0.1" header that is ideal to connect with a microcontroller dev board such as a Seeeduino or an ESP32 DevKit.

Connecting an uSD card to your project allows you to display images that exceed your microcontroller"s available memory. Perfect for all display types, including OLED, TFT, ePaper, etc. We use an uSD card and breakout board to show image slideshows on little OLED displays, as well as hold large demos for our EVE display modules, and playing a video on a TFT.

This uSD breakout board is designed for 3.3v microcontrollers like the Seeeduino or Raspberry Pi. To use with a 5v source, it will require external level shifters for each signal.

This tutorial will explore the range of capabilities available to the Arduino SD library by using a real-world example of data logging. The SD library allows users to read/write, list files, create/remove files, and make/delete directories. Additionally, we will develop an algorithm that creates a new file every time the Arduino board is restarted, which will prevent overwriting of existing data records. The resulting data file will be in comma separated format and contain multiple data points, including a time stamp in milliseconds since the program started. Therefore, it is important to record the program start time. For very accurate time monitoring tasks, a real-time clock is recommended, however, for the experiments conducted here, relative time suffices.

The primary components used for this tutorial are the Arduino board and SD card module, as such, those are the only required components. However, a real-world example will be carried out with the BME280 pressure sensor, which outputs pressure, temperature, and humidity. It also contains an algorithm that converts pressure to altitude - so we will be logging that as well. A lithium-polymer (LiPo) battery will be used so that the datalogger can be portable, which requires a breadboard and 3.7V to 5.0V regulator to also be required. Resultantly, the entire parts list is given below for the portable datalogger:

We will start by wiring the entire set of parts to the Arduino board. This will allow us to move from dealing with just the SD card to saving and storing data to the SD card from the BME280 pressure sensor. The wiring digram is shown below:

This tutorial focuses on creating files and saving data to them in a simple and ready-to-use format. Assuming the SD module is correctly wired to the Arduino module adherent to the diagram above, we can start by reading and writing files to the SD card. The micro SD card must be formatted using the FAT16 file system as per the suggestions on the Arduino website [here]. Below is a simple routine that writes and reads data to the SD card, ensuring that the wiring and formatting were done properly:

The code above looks for a file called “test.csv” and deletes it if it already exists and creates it if it doesn’t. Then the program saves headers called “Timestamp” and “Data.” It opens and closes the “test.csv” file each loop and saves the milliseconds since the program started and an iterating integer. If we subsequently run the built-in Arduino SD script called “DumpFile” - which dumps the contents of an SD card, we can see just how the test script above prints out its data to the SD card:

We can also run the built-in Arduino script called “listfiles” to further ensure that our script is working properly. At the top of the printout from listfiles, the “test.csv” file should be printed with its approximate size. These checks all ensure that our program is working properly, along with our SD card module and micro SD card. Moreover, if the user wants to surely verify that the data is being saved, they can always eject the micro SD card and read it on a computer via the USB port. Excel or a similar program should easily read the .csv data.

Ideally, we don’t want to be deleting files and would prefer to iterate over existing files to create an array of files that make sense chronologically. In this tutorial, I will only work with the root directory and create files based on a particular naming convention. Using this convention, we will be able to create up to 1000 unique files running the same program without overwriting. I have created a simplified script based on the “listfiles” SD routine which will list all the files in the root directory of the SD card. That routine is printed below.

The BME280 is wired in I2C mode such that pressure, temperature, and humidity can be read using the “Wire” library on the Arduino. The BME280 library can be downloaded from Adafruit’s website. We will be logging temperature, humidity, pressure, and calculated altitude. To start, I have included a simple demo of the BME280 that prints the aforementioned variables as comma separated values to the serial port. The code is shown below.

Now that we have an idea of what to expect from both the SD module and BME280 pressure sensor, we can save the data to the SD card and verify the results. The full BME280 SD saver code is shown below, which is essentially an implementation of the BME280 code above and the SD saver method, along with the naming convection discussed above that prevents overwriting. The full code is given below and at the project’s GitHub page.

In this tutorial, a simple datalogging system using Arduino was explored using a novel file saving method and real-world data. Using the methods outlined above, the BME280 pressure sensor outputted temperature, humidity, pressure, and altitude, all of which were saved to a unique file onto an SD card. The SD card method is useful for situations where users want to save data over a long period or use a portable solution for taking measurements. Once the data is saved onto the SD card, the user can take the data and process it on any platform by parsing the data using the simple comma separated formatting. This allows for a range of applications in weather, drones, indoor positioning, and other fields where portable or long-term data acquisition is important.

The Arduino SD card module is especially useful for projects & tutorials that require data logging. The Arduino can create a file in an SD card to write and save data using the SD library. So in this tutorial, I am going to show you step by step “How to Read and Write Data in Arduino SD Card“, using an Arduino SD Card Module

An Arduino Micro SD card Module is an SPI (Serial peripheral interface) communication-based device. It is compatible with the TF (TransFlash) SD cards used in mobile phones and can be used to provide some sort of external storage for a microcontroller and microprocessor-based projects, to store different kinds of data types from images to videos. SD cards generally are 3.3V logic level-based devices, but with the aid of the Micro SD card module, the signals are converted to 5v via a logic level converter implemented on the SD card Module.

The design is deliberately bare-bones: a strip of wood, standing upright thanks to two metal brackets, onto which a bunch of components have been screwed, glued and taped. The actual display consists of a row of 14-segment LED modules that can show basic alphanumeric characters; these displays emit white light, but [Michael] added a red color filter in front to give them a more “retro” look.

This device is fully off-grid, so no Internet connection issues will disrupt your flow. A huge database of quotes and a selection of music tracks are stored on a pair of micro SD cards; an MP3 player module handles the music while an Arduino picks a quote, drives the display, and reads the buttons. You can select quotes based on a certain theme: examples include friendship, gardening, money, and love. But if you’re open to anything, you can just set it to “random” and get something from any of the 120 categories.

I want to use the SD card slot on my ‘‘RepRapDiscount Full Graphic Smart controller’’ to read and write data to and from it to my SD card. My question lays in the connection. I…

In this Arduino touch screen tutorial we will learn how to use TFT LCD Touch Screen with Arduino. You can watch the following video or read the written tutorial below.

As an example I am using a 3.2” TFT Touch Screen in a combination with a TFT LCD Arduino Mega Shield. We need a shield because the TFT Touch screen works at 3.3V and the Arduino Mega outputs are 5 V. For the first example I have the HC-SR04 ultrasonic sensor, then for the second example an RGB LED with three resistors and a push button for the game example. Also I had to make a custom made pin header like this, by soldering pin headers and bend on of them so I could insert them in between the Arduino Board and the TFT Shield.

So now I will explain how we can make the home screen of the program. With the setBackColor() function we need to set the background color of the text, black one in our case. Then we need to set the color to white, set the big font and using the print() function, we will print the string “Arduino TFT Tutorial” at the center of the screen and 10 pixels  down the Y – Axis of the screen. Next we will set the color to red and draw the red line below the text. After that we need to set the color back to white, and print the two other strings, “by HowToMechatronics.com” using the small font and “Select Example” using the big font.

In order the code to work and compile you will have to include an addition “.c” file in the same directory with the Arduino sketch. This file is for the third game example and it’s a bitmap of the bird. For more details how this part of the code work  you can check my particular tutorial. Here you can download that file:

I just recently purchased an Arduino Uno 3 and I wanted to make an ultrasonic distance sensor that outputs the readings to a 16x2 LCD. I followed this guide:

http://www.mertarduino.com/using-ultrasonic-distance-sensor-hc-sr04-with-lcd-display-and-arduino/2018/11/22/ but it gave an error when I uploaded the code. The error was: a function definition is not allowed here before "{" token. I don"t know too much about Arduinos, so I need help.

Secure Digital, officially abbreviated as SD, is a proprietary non-volatile flash memory card format developed by the SD Association (SDA) for use in portable devices.

The standard was introduced in August 1999 by joint efforts between SanDisk, Panasonic (Matsushita) and Toshiba as an improvement over MultiMediaCards (MMCs),

The companies also formed the SD Association (SDA), a non-profit organization, in January 2000 to promote and create SD Card standards.trademarked logos owned and licensed by SD-3C to enforce compliance with its specifications and assure users of compatibility.

In 1999, SanDisk, Panasonic (Matsushita), and Toshiba agreed to develop and market the Secure Digital (SD) Memory Card.MultiMediaCard (MMC) and provided digital rights management based on the Secure Digital Music Initiative (SDMI) standard and for the time, a high memory density.

The trademarked "SD" logo was originally developed for the Super Density Disc, which was the unsuccessful Toshiba entry in the DVD format war. For this reason the D within the logo resembles an optical disc.

At the 2000 Consumer Electronics Show (CES) trade show, the three companies announced the creation of the SD Association (SDA) to promote SD cards. The SD Association, headquartered in San Ramon, California, United States, started with about 30 companies and today consists of about 1,000 product manufacturers that make interoperable memory cards and devices. Early samples of the SD cardMB

The microSD removable miniaturized Secure Digital flash memory cards were originally named T-Flash or TF, abbreviations of TransFlash. TransFlash and microSD cards are functionally identical allowing either to operate in devices made for the other.Chief Technology Officer (CTO) and the CTO of Motorola concluded that current memory cards were too large for mobile phones.

This microSDHC card holds 8 billion bytes. Beneath it is a section of a magnetic-core memory (used until the 1970s) that holds eight bytes using 64 cores. The card covers approximately 20 bits (2 1/2 bytes)

The storage density of memory cards has increased significantly throughout the 2010s decade, allowing the earliest devices to offer support for the SD:XC standard, such as the Samsung Galaxy S III and Samsung Galaxy Note II mobile phones, to expand their available storage to several hundreds of gigabytes.

In January 2009, the SDA announced the SDXC family, which supports cards up to 2 TBexFAT filesystem by default.Consumer Electronics Show (CES) 2009 (January 7–10). At the same show, SanDisk and Sony also announced a comparable Memory Stick XC variant with the same 2 TBPanasonic announced plans to produce 64 GB SDXC cards.Sony"s Handycam HDR-CX55V camcorder, Canon"s EOS 550D (also known as Rebel T2i) Digital SLR camera,

In April 2012, Panasonic introduced MicroP2 card format for professional video applications. The cards are essentially full-size SDHC or SDXC UHS-II cards, rated at UHS Speed Class U1.P2 card equipment.

Panasonic MicroP2 cards shipped in March 2013 and were the first UHS-II compliant products on market; initial offer includes a 32GB SDHC card and a 64GB SDXC card.NAND flash technology.

Samsung announced the world"s first EVO Plus 256 GB microSDXC card in May 2016,Western Digital (SanDisk) announced that a prototype of the first 1 TBPhotokina.

In January 2018, Integral Memory unveiled its 512 GB microSDXC card.PNY launched a 512 GB microSDXC card. In June 2018 Kingston announced its Canvas series of MicroSD cards which were capable of capacities up to 512 GB,

Secure Digital includes five card families available in three sizes. The five families are the original Standard-Capacity (SDSC), the High-Capacity (SDHC), the eXtended-Capacity (SDXC), the Ultra-Capacity (SDUC) and the SDIO, which combines input/output functions with data storage.three form factors are the original size, the mini size, and the micro size. Electrically passive adapters allow a smaller card to fit and function in a device built for a larger card. The SD card"s small footprint is an ideal storage medium for smaller, thinner, and more portable electronic devices.

The second-generation Secure Digital (SDSC or Secure Digital Standard Capacity) card was developed to improve on the MultiMediaCard (MMC) standard, which continued to evolve, but in a different direction. Secure Digital changed the MMC design in several ways:

Asymmetrical shape of the sides of the SD card prevent inserting it upside down (whereas an MMC goes in most of the way but makes no contact if inverted).

Most SD cards are 2.1 mm (0.083 inches) thick, compared to 1.4 mm (0.055 inches) for MMCs. The SD specification defines a card called Thin SD with a thickness of 1.4 mm, but they occur only rarely, as the SDA went on to define even smaller form factors.

The SD specification envisioned capacities and transfer rates exceeding those of MMC, and both of these functionalities have grown over time. For a comparison table, see below.

Full-size SD cards do not fit into the slimmer MMC slots, and other issues also affect the ability to use one format in a host device designed for the other.

The Secure Digital High Capacity (SDHC) format, announced in January 2006 and defined in version 2.0 of the SD specification, supports cards with capacities up to 32 GB.

SDHC cards are physically and electrically identical to standard-capacity SD cards (SDSC). The major compatibility issues between SDHC and SDSC cards are the redefinition of the Card-Specific Data (CSD) register in version 2.0 (see below), and the fact that SDHC cards are shipped preformatted with the FAT32 file system.

The Secure Digital eXtended Capacity (SDXC) format, announced in January 2009 and defined in version 3.01 of the SD specification, supports cards up to 2 TB,exFAT file system as a mandatory feature.

Version 3.01 also introduced the Ultra High Speed (UHS) bus for both SDHC and SDXC cards, with interface speeds from 50 MB/s to 104 MB/s for four-bit UHS-I bus.

Version 5.0 was announced in February 2016 at CP+ 2016, and added "Video Speed Class" ratings for UHS cards to handle higher resolution video formats like 8K.

SDXC and SDUC cards are normally formatted using the exFAT file system, thereby limiting their use to a limited set of operating systems. Therefore, exFAT-formatted SDXC cards are not a 100% universally readable exchange medium.

Windows Vista (SP1) and laterOS X (10.6.5 and later) have native support for exFAT.BSD and Linux distributions did not, for legal reasons; though in Linux kernel 5.4 Microsoft open-sourced the spec and allowed the inclusion of an exFAT driver.FUSE module) in order to be able to mount exFAT-formatted volumes.ext4, UFS, or VFAT), alleviating the restrictions associated with exFAT availability.

Except for the change of file system, SDXC cards are mostly backward compatible with SDHC readers, and many SDHC host devices can use SDXC cards if they are first reformatted to the FAT32 file system.

Nevertheless, in order to be fully compliant with the SDXC card specification, some SDXC-capable host devices are firmware-programmed to expect exFATreformat the card.

SD card speed is customarily rated by its sequential read or write speed. The sequential performance aspect is the most relevant for storing and retrieving large files (relative to block sizes internal to the flash memory), such as images and multimedia. Small data (such as file names, sizes and timestamps) falls under the much lower speed limit of random access, which can be the limiting factor in some use cases.

With early SD cards, a few card manufacturers specified the speed as a "times" ("×") rating, which compared the average speed of reading data to that of the original CD-ROM drive. This was superseded by the Speed Class Rating, which guarantees a minimum rate at which data can be written to the card.

The newer families of SD card improve card speed by increasing the bus rate (the frequency of the clock signal that strobes information into and out of the card). Whatever the bus rate, the card can signal to the host that it is "busy" until a read or a write operation is complete. Compliance with a higher speed rating is a guarantee that the card limits its use of the "busy" indication.

Specified in SD version 3.01.UHS104 (SDR104) also support a clock frequency of 208 MHz, which could transfer 104 MB/s. Double data rate operation at 50 MHz (DDR50) is also specified in Version 3.01, and is mandatory for microSDHC and microSDXC cards labeled as UHS-I. In this mode, four bits are transferred when the clock signal rises and another four bits when it falls, transferring an entire byte on each full clock cycle, hence a 50 MB/s operation could be transferred using a 50 MHz clock.

There is a proprietary UHS-I extension primarily by SanDisk that increases transfer speed further to 170 MB/s, called DDR208 (or DDR200). Unlike UHS-II, it does not use additional pins. It achieves this by using the 208 MHz frequency of the standard SDR104 mode, but using DDR transfers.

The SD Express bus was released in June 2018 with SD specification 7.0. It uses a single PCIe lane to provide full-duplex 985 MB/s transfer speed. Supporting cards must also implement the NVM Express storage access protocol. The Express bus can be implemented by SDHC, SDXC, and SDUC cards. For legacy application use, SD Express cards must also support High Speed bus and UHS-I bus. The Express bus re-uses the pin layout of UHS-II cards and reserves the space for additional two pins that may be introduced in the future.

Hosts which implement version 7.0 of the spec allow SD Cards to do direct memory access, which increases the attack surface of the host dramatically in the face of malicious SD cards.

The SD Association defines standard speed classes for SDHC/SDXC cards indicating minimum performance (minimum serial data writing speed). Both read and write speeds must exceed the specified value. The specification defines these classes in terms of performance curves that translate into the following minimum read-write performance levels on an empty card and suitability for different applications:

Speed Class ratings 2, 4, and 6 assert that the card supports the respective number of megabytes per second as a minimum sustained write speed for a card in a fragmented state.

UHS-I and UHS-II cards can use UHS Speed Class rating with two possible grades: class 1 for minimum write performance of at least 10 MB/s ("U1" symbol featuring number 1 inside "U") and class 3 for minimum write performance of 30 MB/s ("U3" symbol featuring 3 inside "U"), targeted at recording 4K video.UHS Speed Grade and contained grades 0 (no symbol) and 1 ("U1" symbol). Manufacturers can also display standard speed class symbols (C2, C4, C6, and C10) alongside, or in place of UHS speed class.

UHS memory cards work best with UHS host devices. The combination lets the user record HD resolution videos with tapeless camcorders while performing other functions. It is also suitable for real-time broadcasts and capturing large HD videos.

Application Performance Class is a newly defined standard from the SD Specification 5.1 and 6.0 which not only define sequential Writing Speeds but also mandates a minimum IOPS for reading and writing. Class A1 requires a minimum of 1500 reading and 500 writing operations per second, while class A2 requires 4000 and 2000 IOPS.

The "×" rating, that was used by some card manufacturers and made obsolete by speed classes, is a multiple of the standard CD-ROM drive speed of 150 KB/sMbit/s). Basic cards transfer data at up to six times (6×) the CD-ROM speed; that is, 900 kbit/s or 7.37 Mbit/s. The 2.0 specificationTranscend and Kingston, report their cards" write speed.

In applications that require sustained write throughput, such as video recording, the device might not perform satisfactorily if the SD card"s class rating falls below a particular speed. For example, a high-definition camcorder may require a card of not less than Class 6, suffering dropouts or corrupted video if a slower card is used. Digital cameras with slow cards may take a noticeable time after taking a photograph before being ready for the next, while the camera writes the first picture.

The speed class rating does not totally characterize card performance. Different cards of the same class may vary considerably while meeting class specifications. A card"s speed depends on many factors, including:

File fragmentation: where there is not sufficient space for a file to be recorded in a contiguous region, it is split into non-contiguous fragments. This does not cause rotational or head-movement delays as with electromechanical hard drives, but may decrease speed⁠ ⁠ ⁠—  for instance, by requiring additional reads and computation to determine where on the card the file"s next fragment is stored.

In addition, speed may vary markedly between writing a large amount of data to a single file (sequential access, as when a digital camera records large photographs or videos) and writing a large number of small files (a random-access use common in smartphones). A study in 2012 found that, in this random-access use, some Class 2 cards achieved a write speed of 1.38 MB/s, while all cards tested of Class 6 or greater (and some of lower Classes; lower Class does not necessarily mean better small-file performance), including those from major manufacturers, were over 100 times slower.

Cards can protect their contents from erasure or modification, prevent access by non-authorized users, and protect copyrighted content using digital rights management.

The host device can command the SD card to become read-only (to reject subsequent commands to write information to it). There are both reversible and irreversible host commands that achieve this.

Most full-size SD cards have a "mechanical write protect switch" allowing the user to advise the host computer that the user wants the device to be treated as read-only. This does not protect the data on the card if the host is compromised: "It is the responsibility of the host to protect the card. The position [i.e., setting] of the write protect switch is unknown to the internal circuitry of the card."

The switch is a sliding tab that covers a notch in the card. The miniSD and microSD formats do not directly support a write protection notch, but they can be inserted into full-size adapters which do.

On the left side, there may be a write-protection notch. If the notch is omitted, the card can be read and written. If the card is notched, it is read-only. If the card has a notch and a sliding tab which covers the notch, the user can slide the tab upward (toward the contacts) to declare the card read/write, or downward to declare it read-only. The diagram to the right shows an orange sliding write-protect tab in both the unlocked and locked positions.

A host device can lock an SD card using a password of up to 16 bytes, typically supplied by the user. A locked card interacts normally with the host device except that it rejects commands to read and write data. A locked card can be unlocked only by providing the same password. The host device can, after supplying the old password, specify a new password or disable locking. Without the password (typically, in the case that the user forgets the password), the host device can command the card to erase all the data on the card for future re-use (except card data under DRM), but there is no way to gain access to the existing data.

Windows Phone 7 devices use SD cards designed for access only by the phone manufacturer or mobile provider. An SD card inserted into the phone underneath the battery compartment becomes locked "to the phone with an automatically generated key" so that "the SD card cannot be read by another phone, device, or PC".Symbian devices, however, are some of the few that can perform the necessary low-level format operations on locked SD cards. It is therefore possible to use a device such as the Nokia N8 to reformat the card for subsequent use in other devices.

A smartSD memory card is a microSD card with an internal "secure element" that allows the transfer of ISO 7816 Application Protocol Data Unit commands to, for example, JavaCard applets running on the internal secure element through the SD bus.

Some of the earliest versions of microSD memory cards with secure elements were developed in 2009 by DeviceFidelity, Inc.,near field communication (NFC) and mobile payments, with the introduction of In2Pay and CredenSE products, later commercialized and certified for mobile contactless transactions by Visa in 2010.

Various implementations of smartSD cards have been done for payment applications and secured authentication.Good Technology partnered with DeviceFidelity to use microSD cards with secure elements for mobile identity and access control.

microSD cards with Secure Elements and NFC (near field communication) support are used for mobile payments, and have been used in direct-to-consumer mobile wallets and mobile banking solutions, some of which were launched by major banks around the world, including Bank of America, US Bank, and Wells Fargo,neobank programs such as moneto, first launched in 2012.

microSD cards with Secure Elements have also been used for secure voice encryption on mobile devices, which allows for one of the highest levels of security in person-to-person voice communications.

In 2011, HID Global partnered with Arizona State University to launch campus access solutions for students using microSD with Secure Element and MiFare technology provided by DeviceFidelity, Inc.

Integrated Wi-Fi – Several companies produce SD cards with built-in Wi-Fi transceivers supporting static security (WEP 40; 104; and 128, WPA-PSK, and WPA2-PSK). The card lets any digital camera with an SD slot transmit captured images over a wireless network, or store the images on the card"s memory until it is in range of a wireless network. Examples include: Eye-Fi / SanDisk, Transcend Wi-Fi, Toshiba FlashAir, Trek Flucard, PQI Air Card and LZeal ez Share.geotag their pictures.

Pre-loaded content – In 2006, SanDisk announced Gruvi, a microSD card with extra digital rights management features, which they intended as a medium for publishing content. SanDisk again announced pre-loaded cards in 2008, under the slotMusic name, this time not using any of the DRM capabilities of the SD card.

Integrated USB connector – The SanDisk SD Plus product can be plugged directly into a USB port without needing a USB card reader.Duo SD product of OCZ Technology and the 3 Way (microSDHC, SDHC, and USB) product of A-DATA, which was available in 2008 only.

Different colors – SanDisk has used various colors of plastic or adhesive label, including a "gaming" line in translucent plastic colors that indicated the card"s capacity.

Integrated display – In 2006, A-DATA announced a Super Info SD card with a digital display that provided a two-character label and showed the amount of unused memory on the card.

A SDIO (Secure Digital Input Output) card is an extension of the SD specification to cover I/O functions. SDIO cards are only fully functional in host devices designed to support their input-output functions (typically PDAs like the Palm Treo, but occasionally laptops or mobile phones). These devices can use the SD slot to support GPS receivers, modems, barcode readers, FM radio tuners, TV tuners, RFID readers, digital cameras, and interfaces to Wi-Fi, Bluetooth, Ethernet, and IrDA. Many other SDIO devices have been proposed, but it is now more common for I/O devices to connect using the USB interface.

SDIO cards support most of the memory commands of SD cards. SDIO cards can be structured as eight logical cards, although currently, the typical way that an SDIO card uses this capability is to structure itself as one I/O card and one memory card.

The SDIO and SD interfaces are mechanically and electrically identical. Host devices built for SDIO cards generally accept SD memory cards without I/O functions. However, the reverse is not true, because host devices need suitable drivers and applications to support the card"s I/O functions. For example, an HP SDIO camera usually does not work with PDAs that do not list it as an accessory. Inserting an SDIO card into any SD slot causes no physical damage nor disruption to the host device, but users may be frustrated that the SDIO card does not function fully when inserted into a seemingly compatible slot. (USB and Bluetooth devices exhibit comparable compatibility issues, although to a lesser extent thanks to standardized USB device classes and Bluetooth profiles.)

The SDIO family comprises Low-Speed and Full-Speed cards. Both types of SDIO cards support SPI and one-bit SD bus types. Low-Speed SDIO cards are allowed to also support the four-bit SD bus; Full-Speed SDIO cards are required to support the four-bit SD bus. To use an SDIO card as a "combo card" (for both memory and I/O), the host device must first select four-bit SD bus operation. Two other unique features of Low-Speed SDIO are a maximum clock rate of 400 kHz for all communications, and the use of Pin 8 as "interrupt" to try to initiate dialogue with the host device.

The one-bit SD protocol was derived from the MMC protocol, which envisioned the ability to put up to three cards on a bus of common signal lines. The cards use open collector interfaces, where a card may pull a line to the low voltage level; the line is at the high voltage level (because of a pull-up resistor) if no card pulls it low. Though the cards shared clock and signal lines, each card had its own chip select line to sense that the host device had selected it.

The SD protocol envisioned the ability to gang 30 cards together without separate chip select lines. The host device would broadcast commands to all cards and identify the card to respond to the command using its unique serial number.

In practice, cards are rarely ganged together because open-collector operation has problems at high speeds and increases power consumption. Newer versions of the SD specification recommend separate lines to each card.

The hardware interface of the card was changed starting with the version 2.0 (new high-speed bus clocks, redefinition of storage capacity bits) and SDHC family (Ultra-high speed (UHS) bus)

Due to their compact size, Secure Digital cards are used in many consumer electronic devices, and have become a widespread means of storing several gigabytes of data in a small size. Devices in which the user may remove and replace cards often, such as digital cameras, camcorders, and video game consoles, tend to use full-sized cards. Devices in which small size is paramount, such as mobile phones, action cameras such as the GoPro Hero series, and camera drones, tend to use microSD cards.

While cloud storage depends on stable internet connection and sufficiently voluminous data plans, memory cards in mobile devices provide location-independent and private storage expansion with much higher transfer rates and no latency (engineering)(§ Real-world performance), enabling applications such as photography and video recording. While data stored internally on bricked devices is inaccessible, data stored on the memory card can be salvaged and accessed externally by the user as mass storage device. A benefit over USB on the go storage expansion is uncompromised ergonomy. The usage of a memory card also protects the mobile phone"s non-replaceable internal storage from weardown from heavy applications such as excessive camera usage and portable FTP server hosting over WiFi Direct. Due to the technical development of memory cards, users of existing mobile devices are able to expand their storage further and priceworthier with time.

Recent versions of major operating systems such as Windows Mobile and Android allow applications to run from microSD cards, creating possibilities for new usage models for SD cards in mobile computing markets, as well as clearing available internal storage space.

SD cards are not the most economical solution in devices that need only a small amount of non-volatile memory, such as station presets in small radios. They may also not present the best choice for applications that require higher storage capacities or speeds as provided by other flash card standards such as CompactFlash. These limitations may be addressed by evolving memory technologies, such as the new SD 7.0 specifications which allow storage capabilities of up to 128 TB.

Many personal computers of all types, including tablets and mobile phones, use SD cards, either through built-in slots or through an active electronic adapter. Adapters exist for the PC card, ExpressBus, USB, FireWire, and the parallel printer port. Active adapters also let SD cards be used in devices designed for other formats, such as CompactFlash. The FlashPath adapter lets SD cards be used in a floppy disk drive.

Some devices such as the Samsung Galaxy Fit (2011) and Samsung Galaxy Note 8.0 (2013) have an SD card compartment located externally and accessible by hand, while it is located under the battery cover on other devices. More recent mobile phones use a pin-hole ejection system for the tray which houses both the memory card and SIM card.

Samsung Pro 64 GB microSDXC original (left) and counterfeit (right): The counterfeit claims to have 64 GB in capacity, but only 8 GB (Class 4 speed) are usable: When trying to write more than 8 GB, data loss occurs. Also used for SanDisk 64 GB fakes.

Images of genuine, questionable, and fake/counterfeit microSD (Secure Digital) cards before and after decapsulation. Details at source, photo by Andrew Huang.

Commonly found on the market are mislabeled or counterfeit Secure Digital cards that report a fake capacity or run slower than labeled.counterfeit products.random data to the SD card until the card"s capacity is reached, and copying them back. The files that were copied back can be tested either by comparing checksums (e.g. MD5), or trying to compress them. The latter approach leverages the fact that counterfeited cards let the user read back files, which then consist of easily compressible uniform data (for example, repeating 0xFFs).

SD/MMC cards replaced Toshiba"s SmartMedia as the dominant memory card format used in digital cameras. In 2001, SmartMedia had achieved nearly 50% use, but by 2005 SD/MMC had achieved over 40% of the digital camera market and SmartMedia"s share had plummeted by 2007.

At this time, all the leading digital camera manufacturers used SD in their consumer product lines, including Canon, Casio, Fujifilm, Kodak, Leica, Nikon, Olympus, Panasonic, Pentax, Ricoh, Samsung, and Sony. Formerly, Olympus and Fujifilm used XD-Picture Cards (xD cards) exclusively, while Sony only used Memory Stick; by early 2010 all three supported SD.

Some prosumer and professional digital cameras continued to offer CompactFlash (CF), either on a second card slot or as the only storage, as CF supports much higher maximum capacities and historically was cheaper for the same capacity.

Although many personal computers accommodate SD cards as an auxiliary storage device using a built-in slot, or can accommodate SD cards by means of a USB adapter, SD cards cannot be used as the primary hard disk through the onboard ATA controller, because none of the SD card variants support ATA signalling. Primary hard disk use requires a separate SD host controllerbootstrapping from a USB interface, an SD card in a USB adapter can be the boot disk, provided it contains an operating system that supports USB access once the bootstrap is complete.

In laptop and tablet computers, memory cards in an integrated memory card reader offer an ergonomical benefit over USB flash drives, as the latter sticks out of the device, and the user would need to be cautious not to bump it while transporting the device, which could damage the USB port. Memory cards have a unified shape and do not reserve a USB port when inserted into a computer"s dedicated card slot.

Since late 2009, newer Apple computers with installed SD card readers have been able to boot in macOS from SD storage devices, when properly formatted to Mac OS Extended file format and the default partition table set to GUID Partition Table.Other file systems below).

SD cards are increasing in usage and popularity among owners of vintage computers like 8-bit Atari. For example SIO2SD (SIO is an Atari port for connecting external devices) is used nowadays. Software for an 8-bit Atari may be included on one SD card that may have less than 4-8 GB of disk size (2019).

In 2008, the SDA specified Embedded SD, "leverag[ing] well-known SD standards" to enable non-removable SD-style devices on printed circuit boards.MMC standard became the de facto standard for embedded systems. SanDisk provides such embedded memory components under the iNAND brand.

Most modern microcontrollers have built-in SPI logic that can interface to an SD card operating in its SPI mode, providing non-volatile storage. Even if a microcontroller lacks the SPI feature, the feature can be emulated by bit banging. For example, a home-brew hack combines spare General Purpose Input/Output (GPIO) pins of the processor of the Linksys WRT54G router with MMC support code from the Linux kernel.

The SD card specification defines three physical sizes. The SD and SDHC families are available in all three sizes, but the SDXC and SDUC families are not available in the mini size, and the SDIO family is not available in the micro size. Smaller cards are usable in larger slots through use of a passive adapter.

Cards may support various combinations of the following bus types and transfer modes. The SPI bus mode and one-bit SD bus mode are mandatory for all SD families, as explained in the next section. Once the host device and the SD card negotiate a bus interface mode, the usage of the numbered pins is the same for all card sizes.

Four-bit SD bus mode: Uses extra pins plus some reassigned pins. This is the same protocol as the one-bit SD bus mode which uses one command and four data lines for faster data transfer. All SD cards support this mode. UHS-I and UHS-II require this bus type.

Two differential lines SD UHS-II mode: Uses two low-voltage differential interfaces to transfer commands and data. UHS-II cards include this interface in addition to the SD bus modes.

The physical interface comprises 9 pins, except that the miniSD card adds two unconnected pins in the center and the microSD card omits one of the two VSS (Ground) pins.

Official pin numbers for each card type (top to bottom): MMC, SD, miniSD, microSD. This shows the evolution from the older MMC, on which SD is based. NOTE: This drawing doesn"t show 8 new UHS-II contacts that were added in spec 4.0.

SD cards and host devices initially communicate through a synchronous one-bit interface, where the host device provides a clock signal that strobes single bits in and out of the SD card. The host device thereby sends 48-bit commands and receives responses. The card can signal that a response will be delayed, but the host device can abort the dialogue.

The command interface is an extension of the MultiMediaCard (MMC) interface. SD cards dropped support for some of the commands in the MMC protocol, but added commands related to copy protection. By using only commands supported by both standards until determining the type of card inserted, a host device can accommodate both SD and MMC cards.

At initial power-up or card insertion, the host device selects either the Serial Peripheral Interface (SPI) bus or the one-bit SD bus by the voltage level present on Pin 1. Thereafter, the host device may issue a command to switch to the four-bit SD bus interface, if the SD card supports it. For various card types, support for the four-bit SD bus is either optional or mandatory.

After determining that the SD card supports it, the host device can also command the SD card to switch to a higher transfer speed. Until determining the card"s capabilities, the host device should not use a clock speed faster than 400 kHz. SD cards other than SDIO (see below) have a "Default Speed" clock rate of 25 MHz. The host device is not required to use the maximum clock speed that the card supports. It may operate at less than the maximum clock speed to conserve power.

The SD specification defines four-bit-wide transfers. (The MMC specification supports this and also defines an eight-bit-wide mode; MMC cards with extended bits were not accepted by the market.) Transferring several bits on each clock pulse improves the card speed. Advanced SD families have also improved speed by offering faster clock frequencies and double data rate (explained here) in a high-speed differential interface (UHS-II).

Like other types of flash memory card, an SD card of any SD family is a block-addressable storage device, in which the host device can read or write fixed-size blocks by specifying their block number.

Most SD cards ship preformatted with one or more MBR partitions, where the first or only partition contains a file system. This lets them operate like the hard disk of a personal computer. Per the SD card specification, an SD card is formatted with MBR and the following file system:

Most consumer products that take an SD card expect that it is partitioned and formatted in this way. Universal support for FAT12, FAT16, FAT16B, and FAT32 allows the use of SDSC and SDHC cards on most host computers with a compatible SD reader, to present the user with the familiar method of named files in a hierarchical directory tree.

On such SD cards, standard utility programs such as Mac OS X"s "SCANDISK can be used to repair a corrupted filing system and sometimes recover deleted files. Defragmentation tools for FAT file systems may be used on such cards. The resulting consolidation of files may provide a marginal improvement in the time required to read or write the file,flash memory; newer technology to increase the storage capacity of a card provides worse write endurance.

When reformatting an SD card with a capacity of at least 32 MBFAT16B with partition type 06h and EBPB 4.1clusters, which are not widely supported.) FAT16B does not support cards above 4 GB

Because the host views the SD card as a block storage device, the card does not require MBR partitions or any specific file system. The card can be reformatted to use any file system the operating system supports. For example:

Under Unix-like operating systems such as Linux or FreeBSD, SD cards can be formatted using the UFS, Ext2, Ext3, Ext4, btrfs, HFS Plus, ReiserFS or F2FS file system. Additionally under Linux, HFS Plus file systems may be accessed for read/write if the "hfsplus" package is installed, and partitioned and formatted if "hfsprogs" is installed. (These package names are correct under Debian, Ubuntu etc., but may differ on other Linux distributions.)

Additionally, as with live USB flash drives, an SD card can have an operating system installed on it. Computers that can boot from an SD card (either using a USB adapter or inserted into the computer"s flash media reader) instead of the hard disk drive may thereby be able to recover from a corrupted hard disk drive.write-locked to preserve the system"s integrity.

The SD Standard allows usage of only the above-mentioned Microsoft FAT file systems and any card produced in the market shall be preloaded with the related standard file system upon its delivery to the market. If any application or user re-formats the card with a non-standard file system the proper operation of the card, including interoperability, cannot be assured.

Reformatting an SD card with a different file system, or even with the same one, may make the card slower, or shorten its lifespan. Some cards use wear leveling, in which frequently modified blocks are mapped to different portions of memory at different times, and some wear-leveling algorithms are designed for the access patterns typical of FAT12, FAT16 or FAT32.

SD/SDHC/SDXC memory cards have a "Protected Area" on the card for the SD standard"s security function. Neither standard formatters nor the SD Association formatter will erase it. The SD Association suggests that devices or software which use the SD security function may format it.

Modern UHS-II cards can consume up to 2.88 W, if the host device supports bus speed mode SDR104 or UHS-II. Minimum power consumption in the case of a UHS-II host is 720 mW.

All SD cards let the host device determine how much information the card can hold, and the specification of each SD family gives the host device a guarantee of the maximum capacity a compliant card reports.

A host device can ask any inserted SD card for its 128-bit identification string (the Card-Specific Data or CSD). In standard-capacity cards (SDSC), 12 bits identify the number of memory clusters (ranging from 1 to 4,096) and 3 bits identify the number of blocks per cluster (which decode to 4, 8, 16, 32, 64, 128, 256, or 512 blocks per cluster). The host device multiplies these figures (as shown in the following section) with the number of bytes per block to determine the card"s capacity in bytes.

Early SDSC host devices that assume 512-byte blocks therefore do not fully support the insertion of 2 GB or 4 GB cards. In some cases, the host device can read data that happens to reside in the first 1 GB of the card. If the assumption is made in the driver software, success may be version-dependent. In addition, any host device might not support a 4 GB SDSC card, since the specification lets it assume that 2 GB is the maximum for these cards.

Later versions state (at Section 4.3.2) that a 2 GB SDSC card shall set its READ_BL_LEN (and WRITE_BL_LEN) to indicate 1024 bytes, so that the above computation correctly reports the card"s capacity; but that, for consistency, the host device shall not request (by CMD16) block lengths over 512 B.

In the definition of SDHC cards in version 2.0, the C_SIZE portion of the CSD is 22 bits and it indicates the memory size in multiples of 512 KB (the C_SIZE_MULT field is removed and READ_BL_LEN is no longer used to compute capacity). Two bits that were formerly reserved now identify the card family: 0 is SDSC; 1 is SDHC or SDXC; 2 and 3 are reserved.

SDXC cards are allowed to use all 22 bits of the C_SIZE field. An SDHC card that did so (reported C_SIZE > 65,375 to indicate a capacity of over 32 GB) would violate the specification. A host device that relied on C_SIZE rather than the specification to determine the card"s maximum capacity might support such a card, but the card might fail in other SDHC-compatible host devices.

Like most memory card formats, SD is covered by numerous patents and trademarks. Excluding SDIO cards, royalties for SD card licenses are imposed for manufacture and sale of memory cards and host adapters (US$1,000/year plus membership at US$1,500/year)

Early versions of the SD specification were available under a non-disclosure agreement (NDA) prohibiting development of open-source drivers. However, the system was eventually reverse-engineered and free software drivers provided access to SD cards not using DRM. Subsequent to the release of most open-source drivers, the SDA provided a simplified version of the specification under a less restrictive license helping reduce some incompatibility issues.

Under a disclaimers agreement, the simplified specification released by the SDA in 2006 – as opposed to that of SD cards – was later extended to the physical layer, ASSD extensions, SDIO, and SDIO Bluetooth Type-A.

Again, most of the information had already been discovered and Linux had a fully free driver for it. Still, building a chip conforming to this specification caused the One Laptop per Child project to claim "the first truly Open Source SD implementation, with no need to obtain an SDI license or sign NDAs to create SD drivers or applications."

The proprietary nature of the complete SD specification affects embedded systems, laptop computers, and some desktop computers; many desktop computers do not have card slots, instead using USB-based card readers if necessary. These card readers present a standard USB mass storage interface to memory cards, thus separating the operating system from the details of the underlying SD interface. However, embedded systems (such as portable music players) usually gain direct access to SD cards and thus need complete programming information. Desktop card readers are themselves embedded systems; their manufacturers have usually paid the SDA for complete access to the SD specifications. Many notebook computers now include SD card readers not based on USB; device drivers for these essentially gain direct access to the SD card, as do embedded systems.

Overall, SD is less open than CompactFlash or USB flash memory drives. Those open standards can be implemented without paying for licensing, royalties, or documentation. (CompactFlash and USB flash drives may require licensing fees for the use of the SDA"s trademarked logos.)

However, SD is much more open than Sony"s Memory Stick, for which no public documentation nor any documented legacy implementation is available. All SD cards can be accessed freely using the well-documented SPI bus.

xD cards are simply 18-pin NAND flash chips in a special package and support the standard command set for raw NAND flash access. Although the raw hardware interface to xD cards is well understood, the layout of its memory contents—necessary for interoperability with xD card readers and digital cameras—is totally undocumented. The consortium that licenses xD cards has not released any technical information to the public.

A malfunctioning SD card can be repaired using specialized equipment, as long as the middle part, containing the flash storage, is not physically damaged. The controller can in this way be circumvented. This might be harder or even impossible in the case of monolithic card, where the controller resides on the same physical die.

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Micro SD Card Module Supports Micro SD Card, Micro SDHC card (high-speed card). The level conversion circuit board that can interface level is 5V or 3.3V. The communication interface is a standard SPI interface

Control Interface: A total of six pins (GND, VCC, MISO, MOSI, SCK, CS), GND to ground, VCC is the power supply, MISO, MOSI, SCK is the SPI bus, CS is the chip select signal pin; 3.3V regulator circuit: LDO regulator output 3.3V as level converter chip, Micro SD card supply.

MicroSD card toward the direction of the control interface MISO signal is also converted to 3.3V, general AVR microcontroller system can read the signal;