PC Fundamentals Presentation 3 – The Motherboard Copyright © 2007 Heathkit Company, Inc. All Rights Reserved Objectives At the end of this presentation, you will be able to: 2 Explain how power is distributed throughout the motherboard. Identify and explain the purpose of several circuits on the motherboard. Identify and explain the purpose of the ISA expansion bus, the PCI expansion bus, and the accelerated graphics port (AGP). Identify and explain the purpose of the DIMMs. Identify and explain the purpose of each of the field replaceable units (FRUs) on the motherboard. 3 Motherboard Form Factors AT-Type Baby or Mini AT ATX-Type LPX Mini LPX Proprietary Designs 4 Evolution of the Motherboard Processors have gone through several generations. Busses have evolved Memory has evolved 5 Evolution of the Pentium Processor I II III D 6 The AT and ATX Motherboards AT ATX 7 AT Motherboard with Pentium CPU 8 Power Distribution Black Wires AT-Motherboard Power Connectors 10 11 Edge View of Motherboard Voltages supplied to the motherboard + 5 Volts - 5 Volts + 12 Volts - 12 Volts 13 Voltage Regulator 14 CPU Socket 15 The MPU 16 The Pin Grid Array (PGA) Socket. 17 MPU Lever 18 18 Fan Heat Sink CPU 19 19 Industry Standard Architecture (ISA) Bus. 8-MHz Speed Supports 8-bit and 16-bit data transfer Used for slow speed operations such as modems and sound cards. 20 ISA BUS 21 16-bit Cards 8-bit Cards 22 22 ISA boards installed. 16-Bit 8-Bit Motherboard 23 Peripheral Component Interconnect (PCI) Bus 33 MHz Handles 32-bit and 64-bit data transfers Processor independent Supports Plug and Play 24 PCI BUS 25 SIMMs 26 Single In-line Memory Module (SIMM) 27 Cache Memory 28 The Chipset The support chips that make the microprocessor a microcomputer. Applications Specific Integrated Circuits (ASICs) that provide the signals, controllers, interfaces and buffers that the system needs to operate. 29 Chipset 30 Main functions of the Chipset A System Controller handles timing, interrupt and DMA control, and power management. A Memory Controller provides interconnection and control of memory systems. A Peripheral Controller connects the MPU to internal and external devices such as disk drives, buses, and peripherals. 31 Super I/O Controller 32 Super I\O Controller Interface to the floppy drive. Interface to serial ports. Interface to parallel ports. 33 Keyboard Controller 34 Keyboard Controller Communicates with the microprocessor in the keyboard. Performs a parity check. Converts serial data from the keyboard into the parallel data needed by the computer. Generates an interrupt to alert the system that a key has been depressed. 35 ROM BIOS 36 Identifying the ROM BIOS. Socket Version # R3.60 37 Electrically-Erasable PROM… EEPROM 38 Real Time Clock 39 The Real Time Clock (RTC) contains: Clock CMOS memory And in some cases the battery. 40 CMOS is used to hold SETUP information. 41 The FRUs on the AT Motherboard include: The MPU Any board plugged into the PCI bus. Any board plugged into the ISA bus. The SIMMs/DIMMs The ROM BIOS 42 ATX Motherboard 43 9.6 ” Early ATX Motherboard 12 ” 44 45 Power Distribution ATX-Motherboard Power Connector 47 Motherboard Power Connector 48 49 Power Supply Output Voltages ATX-Type +5 Volts +12 Volts -12 Volts -5 Volts +3.3 Volts 50 Pentium 4, Heat Sink & Fan 51 PCI Bus 52 AGP 53 Accelerated Graphics Port (AGP) Operates at twice the speed of the PCI bus or at 66MHz. Even higher speed versions are being developed. Mostly used by Video Cards 54 DIMMs 55 Dual In-line Memory Modules (DIMMs) have components and pin connections on both sides of board. 56 Chipset 57 Super I/O Controller 58 ROM BIOS Battery 59 I/O Ports 60 ATX Motherboard Pentium D Processor PCI Bus 61 ATX Motherboard 62 ATX Motherboard DDR DIMM 63 I/O Ports 10101 10101 64 The motherboard is the heart and soul of the computer. PC Fundamentals End Copyright © 2007 Heathkit Company, Inc. All Rights Reserved