The mobile phone itself has a certain memory capacity. In order to meet people's personalized demand for mobile phone memory, many modern mobile phone brands and models have set up external memory, which is what we usually call mobile phone memory cards. The mobile phone memory card 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.
[Edit this paragraph ]MMC card
MMC (Multimedia Card) card was introduced by Siemens and SanDisk, who started CF, in 1997. 1998 65438+ 10 Fourteen companies jointly established the MMC Association (MMCA), with more than 84 members at present. 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 card in the world at present, with a size of only 32 32 mm x 24 mm x1.4 mm. Although it is thicker than SmartMedia, its overall size is smaller and lighter than SmartMedia. Only1.5g ... MMC also puts the storage unit and controller on the card, and the intelligent controller ensures the compatibility and flexibility of MMC.
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 of MMC memory card and a subset of MMC protocol, which is mainly used in systems that only need a few cards (usually 1) and have low data transmission rate (compared with MMC protocol). This mode can minimize the design cost, but the performance is not as good as MMC.
MMC is designed as a low-cost data platform and communication medium, and the interface design is very simple: only 7 pins! The interface cost is less than $0.50, in contrast, the interface cost of SmartMedia and memory stick is higher than $65,438 +0. On the interface, the power supply is 3-pin, and data operation only needs 3-pin serial bus (SPI mode plus 1 pin chip selection).
The working voltage of 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 methods include streaming, multi-block and single block. The minimum data transmission is in blocks, and the default block size is 5 12 bytes.
[Edit this paragraph ]SD card
SD card is a Secure Digital Card, which was developed by Panasonic, Toshiba and Sandisk. It has the characteristics of large capacity, high performance and safety. 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 slightly thicker than MMC card and has much larger capacity. It produces a capacity of1g. 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 card, and most sockets of SD card support MMC card.
Later, RS-SD (reduced size SD)mini-SD and so on appeared.
Mini SD card: full name (mini secure digital memory card). MiniSD card is developed from SD card, and its performance is not much different from that of traditional SD card. MiniSD card, like SD 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 accidentally deleting the stored content. MiniSD card is characterized by its small size (the size is only 2 1.5×20x 1.4mm, which is 40% smaller than the original SD card), stable performance, which can be used with special adapter cards and fully 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 mobile phones, PDA and PDA information terminals.
Now Panasonic has introduced an SD card with a single load of 4GB.
[Edit this paragraph ]miniSD card
Mini-SD card is a smaller memory card, which is more suitable for small mobile phones, based on flash cards used in digital cameras and PDA. 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. But it doesn't have the anti-write locking function like SD card.
? Mini-SD card has two more interfaces than 9 SD cards, 1 1 signal line (Figure 4). The mini SD card has two additional signal lines for future performance expansion. For example, it can be used for antenna connection of near-field communication such as contactless IC. The other nine signal lines of mini-SD card are the same as the standard signal lines of 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 smaller. In the field of SD card and mini SD card, Panasonic is the promoter of industry standards and the main product provider.
[Edit this paragraph] Memory stick card
Sony's memory stick (MS card for short)
Since Sony announced the development of memory sticks in July, 1997, memory sticks have been fully applied in Sony's full range of products. Products with capacities ranging from 4M to 128M can be applied in different ways in 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 it a memory stick in Chinese, but its size is 50mm x 2 1.5mm x 0.28mm and its weight is 4 grams. The connector is a single plane 10 pin connector connected to an independent pin slot, and has a write protection switch. With the increasing emphasis on copyright protection, Sony launched a new MagicGate memory stick in June1999+February 65438. The main change is the addition of Sony's patented copyright protection technology MagicGate, which meets the standard of SDMI.
Sony's memory stick cards are divided into three specifications due to different sizes, namely, memory stick, memory stick PRO and memory stick DUO. At present, the memory capacity is between 16MB- 128MB. The capacity of memory stick Pro is between 256MB- 1GB, and will reach 32GB in the future. DUO memory stick has the smallest capacity, which is between 16MB-32MB. Through an adapter, it can be inserted into the card slot like the original MS card.
MS PRO is a high-grade product in the MS family. Although the appearance is the same as that of the MS card, the transmission speed is improved, and the lowest recording speed is 15Mbps. It can be suitable for recording continuous dynamic images.
[edit this paragraph ]microSD card
Speaking of microSD, we have to mention the T-Flash card (TransFlash) introduced by SanDisk and Motorola in 2004. The microSD card standard was formulated by SD association in 2005 with reference to the relevant standards of T-Flash, and microSD is compatible with T-Flash. Compared with miniSD, microSD is smaller (11mm×15 mm×1.0 mm), only about a quarter of the standard SD card, and it is the smallest memory card on the market at present. Similarly, microSD can also be used as a standard SD card through an adapter card.
[Edit this paragraph ]RS-MMC card
RS-MMC: RS-MMC is a memory card specially designed for multimedia products such as mobile phones, which was introduced by MMC Association in 2002. RS-MMC is much smaller than MMC and can be converted into a standard MMC card through a special adapter.
[Edit this paragraph ]MMC Plus card
MMC Plus: In September 2004, MMC Association launched MMC Plus and MMC Moblie. The size of MMC Plus card is the same as that of ordinary MMC card, and the reading speed is faster. When it works at the frequency of 52MHz and adopts 8-bit data bandwidth mode, the data transmission rate can reach up to 52MB/s, which can meet the needs of digital image storage and other data-intensive applications, such as high-end digital cameras and digital video cameras. At present, some factories and businesses have also introduced low-voltage MMC Plus cards.
[Edit this paragraph ]MMC mobile card
MMC mobile:MMC mobile is also called dual-voltage RS-MMC. In order to obtain better power saving performance, MMC Association has introduced a memory card-MMC Mobile, which can work at low voltage and is compatible with the original RS-MMC. It can work in 1.65~ 19.5V and 2.7~3.6V, and the theoretical transmission speed can reach up to 52 MB/s. It should be pointed out that the size of MMC Mobile is exactly the same as that of RS-MMC. The only difference is that MMC Mobile has 13 gold fingers, so please make no mistake when buying.
[Edit this paragraph] Smart Media Card
Intelligent media, intelligent media card, storage medium. SM card adopts ss FDG/ flash memory card, which has the characteristics of ultra-small, ultra-thin and ultra-light. Its volume is 37 (length) ×45 (width) × 0.76 (thickness) mm, and its weight is1.8g. 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 in Japan. It has a 22-pin interface, the size is 45mm×37mm×0.9mm, and the weight is about1.8gg. Unlike most digital memory cards, SM cards are made of plastic, and the controller is built in 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. Most of the old digital cameras of Olympus and Fuji use SM memory cards, but there are no products using SM memory cards in the new digital cameras.