|Sunday, 03 September 2006|
A typical motherboard comprises a large printed circuit board having a number of components mounted thereon, including a processor coupled to a host or local bus, a chip set, system memory coupled to a memory bus, and a peripheral component interconnect (PCI) bus. A chipset mounted to the motherboard by the manufacturer provides core logic that operatively links the CPU, the memory modules, and other components of the system. A read only memory (ROM) chip containing the system's startup program (firmware) is also mounted to the motherboard. The chip set bridges the PCI bus with the local bus and also bridges the PCI bus to each of an Industry Standard Architecture (ISA) bus and a Small Computer System Interface (SCSI) bus, if present. The chip set may also provide a system memory controller and bridge the memory bus to the local bus (as well as to the PCI bus). In addition, a motherboard typically includes input/output (I/O) connectors, floppy disk and hard disk drive connections, as well as circuitry for controlling any built-in peripheral devices e.g., hard disk drives, floppy disk drives, and CD ROM drives. A typical motherboard housed within a personal computer comprises one or more layers of printed conductors extending at least partially across the motherboard. The printed conductors surface at localized regions of the motherboard. Those regions allow connection of integrated or discreet devices using various connection techniques, such as plug-and-socket, wire wrap, or solder. Modem motherboard systems further comprise a power saving mode. Typically, a computer motherboard includes many input/output (I/O) ports for connecting to various peripherals, and these I/O ports are arranged on the personal computer. Most personal computers also include a dedicated serial port, a dedicated keyboard port, and one or more expansion slots configured to receive expansion cards for augmenting; the PC's functionality. For example, a network expansion card can be inserted into an expansion slot of a general-purpose PC to provide a port for connecting that PC to a local area network (LAN).
Most personal computers are constructed with a single motherboard that provides connection for CPU and other components in the computer. Generally speaking, a motherboard is manufactured so that it can accommodate dissimilar microprocessors, or microprocessors which respond to differing system bus frequencies or power supply voltages. In a typical computer system, a motherboard is integrated with PCI slots to enable customers to plug different PCI cards into the computer for processing output signals. For this reason, the computer chassis typically includes multiple slot openings covered with clamps, which hold the card in place and can be removed before and restored after plugging PCI cards onto the slots. This has been the prevailing configuration of computer chassis. The motherboard is typically permanently attached to the chassis and is also connected to other internal components via cables or internal connectors. In many systems, the motherboard generally extends in a plane between the chassis and the remaining internal components of the system. Most motherboards are secured to the chassis by screws. The motherboard is mounted to the chassis of the electronic device via a plurality of screws extending through holes in the board into the chassis. Screws are inserted through the openings in the chassis and into the openings that are provided in the motherboard for this purpose. The mounting holes on the motherboard are often surrounded by a grounding pad. The grounding pad is a conductive surface that is used as an electrical ground for the motherboard. To enhance the structural integrity of the computer assembly, the integrated circuit packages are typically soldered to the printed circuit board.
Mother boards and their host computer systems are typically required to meet specified standards for mechanical configuration such that system failures are reduced and component interchangeability is maintained. PC/XT is the original open motherboard standard created by IBM for the first home computer, the IBM-PC. The Baby AT (BAT) was also established by IBM at the inception of the IBM personal computer AT (Advanced Technology). The BAT motherboard has the advantage that it is very common, it is easy to insert add-in cards and the design places the central processing unit (CPU) module near the front of the chassis where it is cooled by incoming air. The BAT motherboard has the disadvantage that there is no expansion room for additional I/O connectors out the back of the motherboard. The LPX standard is based on a design by Western Digital, it allows for smaller cases based on the ATX motherboard by arranging the expansion cards in a riser. The LPX motherboard has the advantage that it is common. I/O is integrated on the motherboard and easily goes out the back of the chassis and the CPU usually placed near the front of chassis where it is cooled by incoming air. ATX is the evolution of the Baby AT form factor, it is now the most popular form factor available today. A full size ATX board is 12" wide by 9.6" deep (305 mm x 244 mm). This allows many ATX form factor chassis to accept microATX boards as well.
On the motherboard, in addition to the central processing unit (CPU), the chip set and the slots for installing the interface cards, the motherboard further includes the memory module slot to installing memory modules. The motherboard has a plurality of memory slots. Each of the plurality of memory slots has such a structure that a memory module can be inserted thereto or removed therefrom. A user can install his memory modules offered from different manufacturers with different numbers according to specific requirements. Typically, a memory module comprises several memory devices. The memory used in a normal computer such as the synchronous dynamic random access memory (SDRAM) operates to control data access in response to the rising edges of the system clock signals. The double data rate (DDR) dynamic random access memory can operate to control the data access on both the rising and falling edges of the system clocks. The DDR DRAM has advantage of performing at the double access rate in comparison with the conventional DRAM due to the upgraded memory access speed. According to different requirements of users, the amount of the memory module slots for installing memory modules is variable. In each memory module, several memory chips are arranged on a single module substrate.
A mother board and one or more daughter boards (also referred to as a peripheral card, expansion board, or daughterboard) are used to transfer digital signals between respective assemblies used in a computer or other electronic equipment. The mother and daughter boards may be arranged perpendicular to each other, as in an edge card configuration, depending upon the design of the overall product. Daughter boards are coupled to a motherboard via sockets, to expand the functionality of the motherboard. The daughter boards may contain memory modules, or other expansion units to the motherboard. Generally, one or more card connectors are located on a motherboard, each card connector for receiving a peripheral card. The daughter boards are added to a computer system to enhance that system's capabilities. A peripheral card may provide a network interface, enhanced audio capability, or enhanced graphics. A peripheral card is typically PCI compatible or ISA compatible, such that the peripheral card (and connector) can be coupled to the PCI bus or ISA bus, respectively. The connection between the daughterboards and the motherboards is generally intended to provide for the transmission of power, ground and electrical signals between the daughterboard and the motherboard.