What are the memory interface types

An introduction to the analysis of memory interface types:

The memory interface type of the gold finger is divided according to the number of conductive contacts on the finger of the memory stripe. The conductive contacts on the Goldfinger are also used to refer to pins (PIN numbers). The number of pins used for each interface type varies depending on the type of interface used for different memory.

Notebook memory generally uses 144Pin, 200Pin interface, desktop memory is basically using 168Pin and 184Pin interface. The memory slot type varies, depending on the number of pins used in memory. Currently, the desktop system mainly has Simms, DIMMs and Rimm three types of memory slots, while the notebook memory slots on the Simms and DIMM slots on the basis of the development, the basic principle has not changed, but only a slight change in the number of pins.

1, Gold fingers

The Gold Finger (connectingfinger) is the connecting part of the memory bar to the memory slot, and all signals are transmitted through the gold finger. Golden fingers are made up of gold-plated, electrically conductive contacts that are called golden fingers because of their gilded surface and the electrically conductive contacts arranged like fingers. The gold finger is actually on the CCL through the special process to cover a layer of gold, because the gold is very strong oxidation resistance, but also very strong conductivity. However, because of the high price of gold, more memory is now used as a tin-plated instead. Since the beginning of the 90 's, the tin materials began to popularize, the current motherboard, memory and graphics devices such as gold fingers, almost all of the use of tin materials, only some high-performance server/workstation accessories contact point, will continue to use gold-plated practice, the price of natural and expensive.

The memory processing unit of all data flow, electronic flow, it is through the gold fingers and memory slot contact with the PC system, is the output input port memory. Therefore, its fabrication process is very important for memory connection.

2, Memory slots

The original computer system, through a separate chip to install the memory, then the memory chips are used dip (dualln-linepackage, dual-line plug-in package) package, dip chip is installed in the bus slot in the memory card and system connection, at this time there is no formal memory slot. The biggest problem with dip chips is that it is cumbersome to install, and as time increases, it will gradually shift out of the socket as the system temperature changes over and over again. As the daily computer starts and shuts down, the chip is constantly heated and cooled, and the chip will slowly stray out of the slot. Eventually lead to bad contact, resulting in memory errors.

There's another way in the early days is the memory chip directly welded to the motherboard or expansion card, which effectively avoids the dip chip deviation, but can not expand the memory capacity, and if a chip is damaged, the entire system will not be able to use, can only be re-welded a chip or replace the motherboard containing bad chips. The cost of such a method is great and inconvenient.

For memory storage, most modern systems have replaced a single memory chip by using a single inline memory module (SINGLEINLINEMEMORYMODULE,SIMM) or a dual-row direct-Insert Memory Module (DUALINLINEMEMORYMODULE,DIMM). These small boards are inserted into a special connector on the motherboard or memory card.

Simms gradually replaced by DIMM technology 3, Memory module

1) Simms

Simms (Singleinlinememorymodule, single row inline memory module). The memory strip is connected with the motherboard through the gold finger, and both sides of the memory strip are provided with gold fingers. Gold fingers can provide different signals on both sides, and they can also provide the same signal. Simms is a two-sided gold fingers provide the same signal memory structure, it is used for early fpm and Edddram, the first time can only transfer 8bif data, and then gradually developed 16bit, 32bit Simms module. Of these, 8bit and 16bitSIMM use the 30pin interface, and 32bit use the 72pin interface. After the memory development into the SDRAM era, Simms gradually replaced by the DIMM technology.

Memory 2) DIMM

DIMM (Dualinlinememorymodule, dual-row inline memory module). Quite similar to Simms, unlike the two ends of the DIMM's Goldfinger, which are not interoperable like Simms, they transmit signals independently. Therefore, more data signal transmission needs can be satisfied. The same Dimm,sdram interface with the DDR memory interface is slightly different, SDRAMDIMM 168PinDIMM structure, the golden finger on each side of 84Pin, Gold finger has two card mouth, used to avoid inserting slots, errors will be inserted into the memory reverse, resulting in burning; D The DRDIMM uses 184PinDIMM structure, the gold finger each side has 92Pin, the gold finger only has one card mouth. The difference between the number of cards is the most obvious distinction between the two. DDR2DIMM 240pinDIMM structure, gold finger on each side has 120Pin, and ddrdimm like gold fingers, but also only a card mouth, but the position of the card mouth and Ddrdimm slightly different. Therefore, the DDR memory is not inserted into the DDR2DIMM, the same DDR2 memory is not inserted into the DDRDIMM. Therefore, in some motherboards with Ddrdimm and DDR2DIMM, there is no problem of plugging the memory into the wrong slot.

172PinMicroDIMM notebook memory Different pin DIMM interface contrast. In order to meet the memory size requirements of the laptop, So-dimm (Smalloutlinedimmmodule) is also developed, which is much smaller than the standard DIMM, and the number of pins is not the same. The same so-dimm varies according to the SDRAM and DDR memory specifications. SDRAM So-dimm only 144pin pins, while the DDR So-dimm has 200pin pins. In addition, notebook memory also has MICRODIMM and MINIREGISTEREDDIMM two kinds of interfaces. The DDR of the Microdimm interface is 172PIN,DDR2 214pin; The Miniregistereddimm interface is 244pin, mainly for DDR2 memory.

3) RIMM

RIMM (Rambusinlinememorymodule) is the type of interface used by the Rambus company to produce rdram memory. The RIMM memory is similar to the size of the DIMM, and the Goldfinger is also double-sided. Rimm has also 184Pin of pins, in the middle part of the Goldfinger there are two close to the mouth of the card. Rimm non-ECC version has 16-bit data width, ECC version is 18-bit wide. Due to the high price of rdram memory, such a DIY market is rarely seen, RIMM interface is rare to see.