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Session 4. Motherboards Version: 3. Session Four. Website Intel Motherboards Motherboard Video 1 (15 min) Lecture Motherboard Video 3 (15 min) Lab 2. Motherboard Form Factors. What is a “form factor”? It is a standard.
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Session 4 Motherboards Version: 3
Session Four • Website • Intel Motherboards • Motherboard Video 1 (15 min) • Lecture • Motherboard Video 3 (15 min) • Lab 2
Motherboard Form Factors What is a “form factor”? It is a standard. e.g. tire sizes – a 215/75 x 15 light truck tire is considered to be functionally equivalent regardless of whether it was manufactured by Goodyear, Firestone, B.F. Goodrich, Michelin, etc. • Modern Form Factors • ATX (used in most new PCs today) • Micro-ATX (used in lower cost PCs) • Flex-ATX (used in very low cost PCs) • NLX (New Low profile) • WTX (used in high performance workstations) • Obsolete Form Factors • Baby AT (used in many early Pentium PCs) • Full-size AT (used in many older PCs) • LPX (Low Profile – not truly a standard) • Proprietary (only available from original manufacturer) • Compaq, Hewlett-Packard, Packard Bell
Motherboards (continued) Motherboards are also known as system boards, main boards, and planars • Full-Size AT and Baby-AT motherboards are often referred to as simply “AT” • They are easily recognized by the existence of only one connector that is accessible through the rear of the case of the PC – the 5 pin DIN connector for the keyboard • The Full-Size AT is just a longer version of the Baby-AT. Thus, a Baby-AT board will fit in a case designed for a Full-Size AT, but not the other way around. • LPX – used in Low Profile case PCs • They can be easily recognized by the existence of a “riser card” that plugs into the mother board, which, in turn, has the expansion cards plugged into it. Thus, the expansion cards are parallel to the mother board. • They are not truly a standard.
Motherboards (continued) • ATX motherboard • Developed in the mid-1990’s • Very popular, Superior design • Single “keyed” connector cable from power supply to motherboard (as opposed to the AT, which has two connectors which, if reversed, will destroy the motherboard!) • Easily recognized by having multiple external connectors “hard wired” (soldered) to the motherboard in a stacked configuration • PS/2 (6 pin mini-DIN) keyboard connector • PS/2 mouse connector • Serial ports, Parallel (printer) port • USB ports • Micro-ATX -- ATX based, but physically smaller than ATX, and can be used in an ATX case • Flex-ATX • ATX based, but physically smaller than Micro-ATX, and can be used in an ATX case • Can use only socketed CPU (e.g not Slot 1)
Motherboards (continued) • NLX motherboard • New Low-profile is a standard • Allows usage of modern features (e.g USB) • Like LPX, expansion cards are parallel to motherboard • Unlike LPX, the NLX motherboard plugs into the riser. (LPX riser plugs into motherboard) • Allows ease of service and repair • WTX • Used in high performance workstations • Very new • Emphasizes expandability and power, not low cost or small size
Chipsets • Prior to 1986, a PC motherboard needed many “support” chips (Integrated Circuits - I.C.s ) to allow the CPU to function. • ASIC - Application Specific Integrated Circuit - combines many small functions into a single IC • Fewer parts (I.C.s) on a motherboard results in smaller size and lower manufacturing cost • As of 1994, Intel became the dominant provider of chipsets for PC motherboards • By concurrently developing new chipsets for new processors, Intel assures that the demand for the new processors will develop rapidly
Intel Chipsets Chipset family Processor class (family) 420xx P4 (486) 430xx P5 (Pentium) 440xx P6 (Pentium II, III, Celeron) e.g. 440BX is a powerful and popular chipset (440BX was first to allow 100 MHz memory bus) • A typical chipset is made of 2 or 3 I.C.s • “North Bridge” - high speed, • “South Bridge” - medium speed • “Super I/O” - low speed
Chipsets (continued) • Intel 810, 815, 820, 840 chipsets • Latest generation of Intel chipset technology • Allows incorporation of newest technologies • Integrated audio and video • Fastest and newest memory types • ISA slots are typically not used • Uses a “hub” style architecture (vs. North Bridge, South Bridge, etc.) • Other Chipset manufacturers • VIA Technologies (Apollo, Apollo Pro) • Silicon integrated System (SiS) • Acer Laboratories, Inc. (Ali)
System Buses • Processor Bus • Communication pathway (bus) between CPU and chipset • Runs at “motherboard speed” e.g. 66 MHz, 100 MHz, 133 MHz CPU core (internal) speed is a multiple e.g. 1.5x, 2x, 2.5x, 3x, 3.5x, 4x, etc. • Memory Bus • Communication pathway (bus) between CPU and main memory (RAM) • On newer systems, same speed as Processor Bus • On older systems, may be slower than Processor Bus to accommodate slow memory • Processor Bus and Memory Bus are entirely on the motherboard • To “expand” and customize the capabilities of the PC, there must be a means to “plug in” additional circuitry - how? “Expansion slots”
Expansion Slots • Sound cards, Video cards, Modem cards, etc. plug into expansion slots • Expansion slots need to access system resources • ISA bus - Industry Standard Architecture • Dates back to original IBM PC with 8088 CPU • 8 bits “wide” (data bus) (also called 8 bit ISA) • 8 MHz “fast” • 16 bit ISA • Dates back to IBM AT with 80286 CPU • 16 bits “wide” (data bus) • 8 MHz “fast” • 8 bit ISA cards function in 16 bit ISA slots • 16 bit ISA slots are still used in many modern motherboards • Newest Intel 810, 820, etc. chipsets do not support ISA
Expansion Slots (continued) • MCA bus - Micro Channel Architecture • Dates back to IBM PS/2 computers • 80386 DX CPU introduces 32 bit data bus • MCA is 32 bits wide • MCA design is technologically superior • IBM made MCA a “closed architecture” - essentially, only IBM sold MCA cards • MCA and ISA are not compatible • MCA is obsolete • EISA bus - Extended ISA • Designed to compete with MCA • Resembles ISA, but with “extended” (dual row) edge connector • ISA cards work in EISA slots • EISA is obsolete
Expansion Slots (continued) • VESA Local Bus (VL Bus) • Video Electronics Standards Association • VESA Local Bus uses an in-line extension of the ISA bus • Poorly designed • VESA Local Bus is obsolete • PCI Bus - Peripheral Component Interconnect • 32 bits “wide” (data bus) • 33 MHz “fast” • Very popular and widespread • Higher speeds of PCI are available • AGP - Accelerated Graphics Port • Video oriented • 32 bit, 66 MHz (2x, 4X and 8x modes exist) • Increasingly common for video card (adapter)
System Resources • IRQ channels - Interrupt Request • DMA channels - Direct Memory Access • I/O Port Addresses (Input/Output) • Memory Addresses • IRQ channels • Interrupt I/O versus Polled I/O • Polled I/O - CPU continuously “polls” I/O devices to see if they need work done by CPU (easy to implement, but very inefficient) • Interrupt I/O - CPU is interrupted by device needing service (CPU suspends current work, executes Interrupt Service Routine for device, and returns to suspended work) (harder to implement, but highly efficient) • Generally, IRQ channels should not be shared (results in device conflict) • IRQ channels are the most challenging resource to manage - large need, small supply
System Resources • DMA channels • Allow high speed data transfers not using CPU • e.g. Hard drive - data is being transferred without any calculation - thus no need for CPU • 8 DMA channels exist, but only 7 are available • Fewer conflicts likely to occur with DMA channels • I/O Ports • Communication ports between hardware and software • Does use CPU • Ports behave like memory addresses, but are a different CPU operation • There are 64 K (65,536) I/O ports (thus, least likely to have conflicts) • Read documentation for new devices! • e.g. a sound card might require 1 IRQ channel, 2 DMA channels, and multiple I/O ports • Maintain documentation for existing systems and devices! (System Configuration Template)