mobile phones themselves have a certain memory capacity. In order to meet people's personalized demand for mobile phone memory, many modern mobile phone brands and models are equipped with external memory, which is what we usually call mobile phone memory cards. Mobile phone memory cards can be used to store data information such as songs, movies, e-books and game software. Now the common memory cards on the market are divided into MMC, SD, MiniSD, Memory Stick, SM and so on.
MMC
MMC(MultiMedia Card) card was introduced by Siemens and SanDisk, which pioneered CF, in 1997. In January 1998, fourteen companies jointly established the MMC Association (MMCA for short), and now it has more than 84 members. The development goal of MMC is mainly aimed at digital images, music, mobile phones, PDA, e-books, toys and other products. It is claimed to be the smallest Flash Memory storage card in the world at present, with a size of only 32 mm x 24 mm x 1.4 mm. Although it is thicker than SmartMedia, its overall volume is smaller and lighter than SmartMedia, only 1.5g.. MMC also puts the storage unit and the controller together on the card, and the intelligent controller makes MMC ensure compatibility and flexibility.
MMC memory cards can be divided into two working modes: MMC and SPI. MMC mode is the standard default mode and has all the characteristics of MMC. SPI mode is the second mode that MMC memory card can choose. This mode is a subset of MMC protocol, which is mainly used in systems that only need a small number of cards (usually one) and have low data transmission rate (compared with MMC protocol). This mode can minimize the design cost, but its performance is not as good as MMC.
MMC is designed as a low-cost data platform and communication medium, and its interface design is very simple: only 7 pins! The interface cost is less than $.5, in contrast, the interface cost of SmartMedia and Memory Stick is more than $1. In the interface, the power supply is 3 pins, and the data operation only needs a 3-pin serial bus (SPI mode plus 1 pin for chip selection).
the operating voltage of p>MMC is 2.7 volts to 3.6 volts, and the write/read current is only 27mA and 23mA, so the power consumption is very low. Its reading and writing modes include streaming, multi-block and single block. The minimum data transfer is in blocks, and the default block size is 512bytes.
p>SD
Super Dollfie is referred to as SD for short,
is a 1/3 spherical joint movable doll manufactured by volks Company of Japan, and
is developed and molded by Master Akio Hiroshi.
Generally, SD is 58cm high,
There are 13-year-old SD with a height of 6cm and mini SD with a height of 43cm.
The prices are all different, generally around RMB 4,5-8,5, and
mini SD is also around RMB 2,-4,.
The feature of SD is that players can modify it by themselves.
Because the eyes, hair, body joints, hands, feet, arms and legs of SD can be separated,
Players who can't assemble can buy the assembled SD.
It is precisely because of these flexible joints that
the SD dolls we see can Pose so many poses, which are
chic or elegant.
In addition, players can make up their own faces of SD.
Whether it's eyebrows, eyelashes, eyeliner, lip gloss or even facial rouge,
players can dress up their SD as a beautiful woman or a handsome guy who looks better than Pan An, and
shape your unique SD.
It is precisely because an SD can show thousands of customs because of different hair colors, eye colors, ever-changing gorgeous clothes and different dresses
that it is more popular.
Because the threshold is too high, SD players are mainly Generation X who have not lost their childlike innocence but have started to earn money. IMAI, who runs her own doll studio, always has six SD's. She said that her family also knows that she has this hobby, and now she has "given up on her".
In the doll circle in Taipei, there are dozens of people playing with SD dolls, from all walks of life, and even a young female dentist, Huohuo, not only uses the dentist's skills to trim the doll's face, but also takes SD abroad to take outdoor photos for SD in Switzerland with lakes and mountains.
In addition to this young group on the table, "Guifuren" is also a super-large household of SD, Momoko and Jenny dolls. She often starts with 5, yuan or 1, yuan. She does not hesitate to buy clothes, but because of her status, she never comes into contact with ordinary players.
SD dolls have attracted many male players because of their exquisiteness. Xiong Xiong and his sister Xiong Mei, who are engaged in art design, joined in last year. At present, there are six SD's, and the investment amount exceeds 2,. Xiong Xiong said, "I can't even think about how much it cost. It's really terrible. Nakururu, who is engaged in Japanese translation, started playing SD herself because of her girlfriend.
Every other month or so, these players will hold a "doll get-together", because everyone doesn't have many SD's, most of them only have one or two. After bringing the dolls to the venue with the original large paper boxes or violin cases, they will take this opportunity to play with other people's dolls more, or let the dolls pose in some special positions, such as letting the boys hug the boys' "BL", which is very popular among female players.
In addition, players will exchange "Mother's Sutra" and "Maintenance Sutra". "I use conditioner to help her wash her hair, so that she won't be short-tempered! "This hairstyle is so cute" and "Your pants are made of curtain cloth, right?
At present, most of the dolls popular in the market are "one sixth" and "one third". The former is about 3 cm high, with Jenny, Lika and Momoko for girls and soldier dolls for boys, while the latter is about 6 cm high. At present, only SD is popular.
SD dolls have different heights, the average SD is 58cm, the miniSD is 43cm, and the latest SD13(13 refers to a girl who looks like a 13-year-old) is 6cm. These SD's joints can move, they can change their hair, they can change the color of their eyes, and you can help them change their makeup bundles and face shapes.
in the internet, SD is often used to swear words, which is the first letter of the Chinese character "silly cock".
and explain that I <; Yes >
SD is also synonymous with Shanghai Shanda Network Company.
In the electronic industry,
SD card is SecureDigitalCard—-secure digital memory card, which is a multi-functional memory card with large capacity, high performance, safety and other characteristics, developed by Panasonic, Toshiba and SANDISK of the United States. Compared with MMC, it has a password authentication function (SDMI specification) for data copyright protection. Mainly used in Panasonic digital cameras, cameras, Canon and Sharp cameras, Kodak, Minolta, Casio digital cameras and other manufacturers. The size is 32mm×24mm×2.1mm, which is a little thicker than MMC card and has a much larger capacity. It has produced a capacity of 1G. The reading and writing speed of this card is 4 times faster than that of MMC card, reaching 2MB/ s.. At the same time, it is compatible with MMC cards, and most sockets of SD cards support MMC cards.
later, RS-SD(Reduce size SD)mini-SD and other
Mini SD cards: Mini Secure Digital Memory Card appeared. MiniSD card is developed from SD card, and its performance is not much different from that of traditional SD card. Like SD card, miniSD card has a data transmission speed of 2MB per second. Like the traditional SD card, the miniSD card also has a hardware data write protection switch, which can avoid the risk of accidental deletion of stored content. MiniSD card is characterized by its small size (only 21.5×2x1.4mm, which is 4% smaller than the original SD card), stable performance, and can be used with special adapter cards, which is completely compatible with standard SD card slots. Moreover, the miniSD card is designed with low power consumption, which is more suitable for mobile communication devices than the SD card, so it mainly attacks the information terminals of mobile phones, PDA's and PDA's.
Now Panasonic has launched an SD card with a single load of 4GB.
miniSD
mini-SD card is a smaller memory card which is more suitable for small mobile phones, based on the Flash Memory Card used in digital cameras, PDA, etc. Although the mini-SD card is different from the original SD card in appearance size and interface shape, the electrical standards such as interface are the same to ensure compatibility. Insert the mini-SD card into the special adapter, and you can read and write the mini-SD card through the original SD card slot. However, it does not have the lock function of preventing writing like SD card. Mini-SD card has 2 more interfaces than the 9 SD cards, and has 11 signal lines (Figure 4). The two extra signal lines of mini-SD card are for future performance expansion. For example, it can be used for antenna connection of near field communication such as contactless IC. The remaining nine signal lines of mini-SD card are the same standard signal lines as the original SD card. Mini-SD card is a small SD card specially developed for digital devices such as mobile phones. Compared with SD card, Mini-SD card is more compact. In the field of SD card and Mini-SD card, Panasonic is the promoter of industry standards and the main product provider.
Memory Stick
SONY's Memory Stick (MS card for short)
Since SONY announced the development of Memory Stick in July, 1997, Memory Stick has been fully applied to SONY's full range of products, and products with a capacity from 4M to 128M can be used in different ways on SONY's own products. Sony, which has the richest product line of digital equipment, even tries to make this Flash Memory an industry standard. SONY calls its Chinese name memory stick, but its size is 5mm x 21.5mm x .28mm and its weight is 4 grams. The product is connected to the independent needle slot by a single plane 1-pin adapter, and has a write-protection switch. In the increasingly stressed demand for copyright protection, Sony introduced a new MagicGate Memory Stick in December 1999. The main change lies in the addition of Sony's patented copyright protection technology called MagicGate, which complies with SDMI standards.
SONY's Memory Stick cards are divided into three specifications due to different dimensions, namely, Memory Stick, Memory Stick PRO and Memory Stick DUO. At present, the capacity of Memory Stick is between 16mb and 128mb. The capacity of Memory Stick Pro is between 256 MB and 1 GB, and will reach 32GB in the future. The capacity of Memory Stick DUO is the smallest, between 16 MB and 32 MB. It can be inserted into the card slot like the original MS card through an adapter.
MS PRO is a high-end product in the MS family. although it has the same shape as the MS card, its transmission speed has been improved, and the minimum recording speed is 15Mbps. It can be adapted to record continuous dynamic images.
3. A smart memory card, a modern scientific term
is Smart Media, a storage medium. SM card adopts SSFDG/Flash memory card, which has the characteristics of ultra-small, ultra-thin and ultra-light. Its volume is 37 (length) ×45 (width) ×.76 (thickness) mm, and its weight is 1.8g It has low power consumption and is easy to upgrade. SM conversion card also has PCMCIA interface, which is convenient for users to transmit data.
SM card is a small memory card introduced by Toshiba, Japan. It has a 22-pin interface with a size of 45mm×37mm×.9mm and a weight of about 1.8g. Different from most digital memory cards, SM card is made of plastic, and the controller is built into the digital camera. Because the compatibility of the camera is not strong, it has not been widely promoted by manufacturers, and the maximum capacity of the product is also very limited. The maximum storage capacity of SM card is only 128MB. The old digital cameras of Olympus and Fuji mostly use SM memory cards, and there are no products that use SM memory cards in the new digital cameras.