What is an expansion card

One: What is flash memory? In the past, people used film for photography, tape for tape, video tape for recording, disk for storage, and development of technology, especially the development of digital products, which prompted the birth of flash cards. . At present, flash memory cards have a wide range of applications, which have led to the rapid development of flash memory cards. Now, photo storage, video storage, music storage, and other data can all be replaced by flash memory cards.

Flash memory: Flash memory uses a new type of EEPROM memory (electrically erasable, programmable, and read-only memory) that has the advantages of memory erasable, programmable, and programmable, and it also has the advantage that written data will not be lost after a power failure. . All are widely used for digital cameras, MP3s, and mobile storage devices.

Flash Card: Flash Card is a memory that uses flash memory technology to store electronic information. It is generally used as a storage medium in digital cameras, PDAs, MP3s, and other small digital products. Therefore, it looks like a small card. Cards, so called flash cards.

Second: The classification of flash memory cards is due to different manufacturers, different equipment, and different uses, so the flash memory cards are divided into six categories and twelve subcategories.

SD Card CF Card MMC Card XD Card SM Card SONY Memory Stick Minisd Card T-Flash Card CFI Card CFII Card Rsmmc Card DVrsmmc Card Sony mspro Long Stick Sony mspro duo Short Stick SD Card:

Secure Digital Memory Card is a new generation memory device based on semiconductor flash memory. The SD card was jointly developed by Panasonic, Toshiba and SanDisk in the United States in August 1999. An SD memory card, the size of a stamp, weighs only 2 grams, but it has high memory capacity, fast data transfer rate, great mobility flexibility, and good security.

CF card:

CompactFlash was first introduced by SanDisk in 1994. The CF card has PCMCIA-ATA functionality and is compatible with it; the CF card weighs only 14g and is just cardboard-sized (43mm x 36m x m3.3mm). It is a solid-state product, that is, it has no moving parts during operation.


MMC card:

The MMC (MultiMedia Card) card was launched in 1997 by Siemens and SanDisk, the first CF. In January 1998, 14 companies jointly established the MMC Association (MMCA). Now it has more than 84 members, and its appearance is similar to that of SD cards. A few pins are missing.

XD card:

The XD card is called the XD-PICTURE CARD. It is a compact memory card specially developed for digital cameras by Fujifilm and Olympus. It uses a single-sided 18-pin interface and is the smallest memory card currently available. . XD is derived from "Extreme Digital," meaning "limit number." The XD card is a relatively new kind of flash memory card, which has many advantages compared to other flash memory cards. The compact size, external dimensions of 20mm × 25mm × 1.7mm, the total volume of only 0.85 cubic centimeters, is about 2 grams, is the world's most lightweight, smallest digital flash memory card SM card:

The SM (Smart Media) card was a Flash Memory memory card issued by Toshiba in November 1995. Samsung acquired a production and sales license in 1996. The two companies became major SM card manufacturers. The size of the SM card is 37mm × 45mm × 0.76mm (Figure 1), because the SM card itself does not have a control circuit, but also made of plastic (is divided into many thin slices), so the SM card's small size is very thin and thin SONY memory stick:

Sony ms (Memory Stick): Sony's unique character has created the memory stick. This chewing gum-type storage device can be used almost universally in all Sony audio and video products. The Memory Stick is lightweight and has a full range of functions. Its high compatibility and unprecedented "Universal Media" concept provide a new generation of higher speed, higher capacity for future high-tech personal computers, televisions, phones, digital cameras, video cameras and portable personal audio-visual equipment. Digital information storage, exchange media.

Three: Use of flash memory cards n Use to store photos on digital cameras n Use to store music files, files, movie videos on mobile phones n Use to store video on DV (digital video camera) n Use to store data on GPS n Use Industrial control on the storage of program software and other n for MP3, MP4, digital voice recorders, etc. n for...

Four: The development trend of flash memory cards Due to the many advantages of flash memory cards and the application fields of flash memory cards, flash memory cards have gradually replaced traditional storage media and become the main force in the future storage industry. Mainly reflected in digital cameras and mobile phones other electronic storage areas. Its potential is unlimited and the market is huge. Imagine that due to the continuous popularization and popularization of smart phones and 3G mobile phones, China’s communications industry is maturing. With the growth of smart phones and the increasing number of users of 3G mobile phones, the demand for mobile phone special flash cards will grow. Future flash memory will lead the entire electronic information storage world.

Five: flash memory card technology and parameter transmission rate: Generally calculated according to the double speed. x 1x is 150KB There are many 60X and 80X high-speed cards on the market. The higher the speed, the faster the speed.

Read speed and write speed: refers to the flash read and write operations, this speed will be based on the flash memory card control chip to determine the speed of the flash card, read speed and write speed will be different.

Control Chip: Provides superior functionality and enhances your memory card performance. High-speed transmission speed (transmission speed), excellent compatibility, so that your stored data is foolproof (safety).

Voltage: Different types of flash memory cards have different specifications, and the voltage they can operate normally is different. However, different flash memory card interfaces are also different, and there is no possibility of inserting wrong interfaces. Therefore, there is no case where the flash memory card is damaged due to a different working voltage due to the wrong insertion and connection. Typical Operating Voltage: CF Card: 3.3V/5V SD Card: 2.7-3.6V SM: 3.3V DVRSMMC: 1.8/3.3V

Six: The failure of the flash memory card and troubleshooting of flash memory cards are as follows:

1. One or several photos stored cannot be opened 2. Prompt that one photo or several photos are damaged 3. The flash memory card needs to be formatted 4. The prompt space is full or the space is insufficient (only a few photos are actually taken)

5. Prompt card error 6. Prompt that the card cannot be found or the card has not been inserted. 7. The copied music or text cannot be opened, or the music file cannot be played. The text is completely garbled. What causes the above phenomenon:

1, when the battery voltage is too low to write data in 2, not according to the prompt to insert or remove the card 3, is suddenly lost power when writing data to the card 4, there is not enough space to hard write data 5, incorrect Continuous shooting 6, viral reasons 7, some unknown human reasons...

How to solve the above troubleshooting 1, due to the above-mentioned incorrect operation directly led to a logical failure of the flash memory card, flash memory card control chip detects the above incorrect operation in order to protect the card's FLASH from damage, the flash card is not burned, flash memory card A logical lock is automatically added, which is the automatic protection of the flash memory card. The purpose is to protect the flash memory card.

2. After being locked, we can connect to the card reader or format it directly on the digital device through a computer. General faults can be eliminated directly.

3, if the format fails, you can use a professional software to format or low-level formatting.

4, if the virus causes, we can use anti-virus software to remove the virus and achieve the purpose of repairing the card.

5, if there is important data we can restore through professional data recovery software (described later).

Seven: The use of flash memory card 1, when using flash memory card, try to avoid hot-plug flash memory card.

2. It is best not to use a flash memory card to write or read data when the digital device is running out of power, or when the battery is being alarmed.

3, in the process of using flash memory card, try to set aside some space.

4, in the case of continuous shooting is not supported (1 is the camera does not support, 2 is the speed of the card can not keep up) it is best not continuous shooting.

5, try to avoid the virus infection.

6. Try to avoid using flash memory cards on non-compliant devices.

7, digital flash memory card as far as possible to take care to gently, do not use force to fall, hit, pinch, etc., easy to cause damage; avoid contact with high temperature, high humidity, strong magnetic field, strong electric field place.

Eight: Data security of flash memory cards Data security mainly involves some correct operations to ensure data security. 1: When you encounter a single piece of data or several pictures cannot be opened, it is best to save good pictures first, to avoid More data was destroyed when taking photos later.

2: When prompted to format the card, it is best not to format or write the read data yourself, and not to insert a repeated test card in the camera.

3: When encountering viruses or other reasons, it is best not to tamper with them for the time being, in order to avoid data destruction. The first time, you will get professional service points for data recovery.

Nine: The use of mobile flash memory cards and troubleshooting 1, clearly on the phone due to mobile phone readers and other reasons, there are some differences between his format and the format on the computer, so it is best to be formatted on the phone, so After formatting, some specific directories will be automatically generated on the phone (this will vary depending on the phone).

2, different files are stored in different directories, some customers react to MP3, movies, etc. can not be copied into the card, because the phone can only read the card when reading the corresponding directory, such as playing music, the phone will be in AUDIO Or find the corresponding directory in the MP3 directory for the VIDEO directory, of course, different mobile phones also have their own directory, not all mobile phones are stored in this way, some mobile phones can manually create a directory, and some mobile phones do not recognize Manually created directory, this depends on the actual situation of the phone.

3, mobile phone will detect the memory card during the boot process, there will be a process, start slowly, do not pull out the memory card at this time, so as not to cause damage to the flash memory card.

4, due to the format of the phone or mobile phone support files are different, we should copy the corresponding file for his data (for example, some mobile phones support MP4, and some phones support 3GP file format)

5, some mobile phones do not support the large-capacity card itself, some mobile phone compatibility issues, making the card use very unstable (such as Nokia QD, the use of 128 or more cards is very unstable.)

7, the same, when the cell phone battery voltage is too low, it is best not to write something or open the card inside the file.