1. Copyright © 2007 Heathkit Company, Inc. All Rights Reserved PC Fundamentals Presentation 35 – Buses

2. 2 Objectives At the end of this presentation, you will be able to:

3. 3 Define computer bus and explain its purpose. Define the following terms: ISA, MCA, EISA, VL-Bus, PCI, PCI Express, and AGP. Discuss the characteristics of the PCI, PCI Express, and AGP buses. Recognize the connector (or slot) of an ISA, PCI, PCI Express, and VGA bus.

4. 4 CPU Memory Keyboard Controller Parallel Port System Controller Video Adapter Video Adapter The Data Bus

5. 5 Keyboard Controller System Controller Video Adapter Video Adapter CPU Memory

6. 6 Video Adapter Video Adapter CPU

7. 7 CPU Socket (Slot 1) System Controller Bus Wires

8. 8 What is a Bus? Signal Pathways A way of passing information between components inside and outside the computer. A modular way of expanding the functions or capabilities of the computer.

9. 9 PC Bus Architectures ISA MCA EISA VL-Bus PCI AGP PCI Express

10. 10 The Original IBM PC Bus Introduced on the original IBM PC 8- bit data path 4.77-MHz clock 8 Interrupts - Only one of which was available for expansion boards. 4 DMA Channels - Only one of which was available for expansion boards.

11. 11 8-Bit Card 8-Bit Slot The Original IBM PC Bus

12. 12 Industry Standard Architecture (ISA) Bus Introduced on the IBM AT Computer 16-bit data path Backward compatible with IBM-PC Bus 8-MHz clock 15 Interrupts 7 DMA Channels

13. 13 16-Bit Card 16-Bit Slot Industry Standard Architecture (ISA) Bus 8-Bit Section Added Pins

14. 14 16-Bit Slot Industry Standard Architecture (ISA) Bus 8-Bit Card

15. 15 Micro-Channel Architecture (MCA) Bus Introduced on the IBM PS/2 16-bit or 32-bit data path 10-MHz clock Configured by software rather than by jumpers or switches Not compatible with the ISA bus Bus Mastering

16. 16 Bus Mastering Allows data to be passed from one device to another without CPU intervention. Allows a controller card to take control of the bus, leaving the CPU free to concentrate on other tasks.

17. 17 Bus Mastering vs. DMA DMA can send data from peripheral to RAM or from RAM to peripheral, without the intervention of the CPU. Bus Mastering can send data from peripheral to peripheral, without the intervention of the CPU.

18. 18 Extended ISA Bus (EISA) The industrys answer to the MCA bus Backward compatible with ISA 16-bit or 32-bit data path 8-MHz Clock Configured by software, not jumpers or switches Bus Mastering

19. 19 CPU BUS Controller BUS Controller ISA Bus Slots ISA Bus Slots High Speed CPU Bus High Speed CPU Bus Low Speed I/O Bus Low Speed I/O Bus

20. 20 CPU BUS Controller BUS Controller ISA Bus Slots ISA Bus Slots Local Bus Slots Local Bus Slots High Speed CPU Bus High Speed CPU Bus Low Speed I/O Bus Low Speed I/O Bus

21. 21 VESA Local Bus (VL-Bus) Clock speed same as the processor 32-bit data path Regular ISA slot with local bus connector added Bus Mastering

22. 22 Peripheral Component Interconnect (PCI) Developed for Pentium-class processors 32-bit and 64-bit data path versions 33-MHz Clock Processor Independent Plug and Play with Bus Mastering

23. 23 Peripheral Component Interconnect (PCI) Bus

24. 24 PCI Evolution 32-bit, 33 MHz 64-bit, 33 MHz 32-bit, 66 MHz 64-bit, 66 MHz

25. 25 PCI-X PCI-X 6664-bit66 MHz PCI-X 13364-bit133 MHz PCI-X 26664-bit266 MHz PCI-X 53364-bit533 MHz

26. 26 PCI Express The next generation of PCI. Serial data paths. Very high speed (2500 MHz) Scales easily as additional serial data paths are added. X1 has one serial path, X4 four serial paths, etc.

27. 27 PCI-Express @ 2500 MHz PCI Express x11250 Mbps PCI Express x441000 Mbps PCI Express x882000 Mbps PCI Express x16164000 Mbps PCI Express x32328000 Mbps Lanes Bandwidth

28. 28 PCI and PCI Express Slots Conventional PCI PCI Express X 16 PCI Express X 1

29. 29 Accelerated Graphics Port (AGP) Developed for high speed graphics cards Frees the PCI bus from making video transfers Used only for video cards Considered a port rather than a bus 66 MHz, 32-Bit

30. 30 Accelerated Graphics Port (AGP)

31. 31 AGP Modes 32-bits @ 66 MHz AGP 1266 Mbps AGP 2X2533 Mbps AGP 4X41066 Mbps AGP 8X82133 Mbps Bandwidth Data Cycles Per Clock

32. Copyright © 2007 Heathkit Company, Inc. All Rights Reserved PC Fundamentals End