1. Chapter 5 Supporting I/O Devices

2. You Will Learn… • How to install peripheral I/O devices • How to use ports and expansion slots for add-on devices • About keyboards and how to troubleshoot them • About different types of pointing devices • How monitors and video cards relate to the system, and how to troubleshoot them

3. Basic Principles of Peripheral Installations • Peripheral is a hardware device controlled by software; must install both hardware and software • Software might be of different types; you must install all levels • More than one peripheral device might attempt to use same computer resources (IRQ, DMA channel, I/O addresses, or [for 16-bit drivers] upper memory addresses)

4. A Review of System Resources • An IRQ is a line on a bus that serves as an interrupt request line and is assigned to a device • Each device needs a group of I/O addresses the CPU will use to get the attention of the device and communicate with it • Older device drivers and BIOS written in real mode require some upper memory addresses 640K-1024K • Some devices require a DMA channel to speed up data transfer across the bus continued…

5. A Review of System Resources • System resources are assigned at startup • PnP devices do not request specific I/O addresses, DMA channels, or IRQs, but use those assigned by BIOS and OS • Legacy devices are not PnP and require special memory resources • Sometimes a bus controller is assigned a single set of resources for all devices using the bus

6. Installation Overview for an Add-on Device • Install device (internal or external) • Install device driver • Install application software

7. Internal Devices • Drives (eg, hard, floppy, CD-ROM, DVD, Zip) • Devices that are inserted in expansion slots on the motherboard • Advantages • Less expensive than external devices • Don’t take up desk space

8. External Devices • Use existing port (eg, serial, parallel, USB, IEEE 1394) • Use port provided by interface card installed in expansion slot • Advantage • Can be moved easily from one computer to another

10. Purchasing a Hardware Device • Have basic knowledge of your system • CPU, system bus, and local bus drive • Memory • Hard drive size • OS and version • Space available on hard drive • For internal devices: how many drives, bays, or expansion slots are available

11. Purchasing a Hardware Device • Plug and Play? • Offers features you want? • Documentation easy to read and comprehensive? • Manufacturer’s Web site offer help and technical support? • Warranty? • Compatible with current hardware and software?

12. Installing a Hardware Device • Use antistatic bracelet and ground mat • Unplug the PC and remove case cover • Locate the slot and remove faceplate • Insert expansion card in expansion slot • Insert screw that connects card to case • Replace case cover, power cord, and peripherals • Plug in the device • Reboot the PC; install device drivers • Test device

13. The Case Cover

14. Screws Connect Card to the Case

15. Using Ports and Expansion Slots for Add-on Devices • Serial ports • Parallel ports • USB ports • IEEE 1394 ports • Expansion slots

16. Serial, Parallel, and Game Ports

17. Using Serial Ports • Transmit data in single bits • Almost always male • Intended for input and output devices • Configurable for COM1, COM2, COM3, or COM4 • Port assignments are made in CMOS setup • Conforms to standard interface called RS-232c • Data Terminal Equipment (DTE) and Data Communications Equipment (DCE) designations

18. Default Port Assignments

19. CMOS Setup Screen

20. Pins on a Serial Port Connection continued…

21. Pins on a Serial Port Connection

22. Null Modem Connection • Special cable (null modem cable or modem eliminator) enables data transmission between two DTE devices without the need for modems

23. Pin Connections for a 25-Pin Null Modem Cable

24. Infrared Transceivers • Use resources of a serial port for communication • Create a virtual infrared serial port and virtual infrared port for infrared devices • Sometimes motherboard provides 5-pin connection for its own proprietary IrDA-compliant infrared transceiver • Industry is moving away from infrared and toward other wireless technologies because of line-of-sight issue

25. The Universal Asynchronous Receiver-Transmitter (UART) Chip • Controls all nine pins of a serial port • Establishes communications protocol • Converts parallel data bits coming from the system bus into serial bits for transmission • Converts incoming serial data bits it receives into parallel form needed by the system bus • UART 16550 driver is built into all Windows operating systems

26. Using Parallel Ports • Transmit data in parallel, eight bits at a time • Almost always female • Originally intended for printers; now also used for input devices • Cable should be no longer than 10 feet to avoid loss of integrity of data • Can be configured as LPT1, LPT2, or LPT3 • Port assignments are made in CMOS setup

27. Uses of the Pin Connections for a 25-Pin Parallel Port continued…

28. Uses of the Pin Connections for a 25-Pin Parallel Port

29. Types of Parallel Ports • Standard parallel port (SPP) • Allows data to flow in only one direction • Slowest of the three types • Enhanced Parallel Port (EPP) • Bi-directional • Extended Capabilities Port (ECP) • Bi-directional

30. A Standard Parallel Port

31. Using USB Ports • Designed to make installation of slow peripheral devices as effortless as possible • Much faster than regular serial ports • Use higher-quality cabling with four wires—two for power and two for communication • Easier to manage; eliminate need to manually resolve resource conflicts continued…

32. Using USB Ports • Allow for hot-swapping and are hot-pluggable • Most current motherboards have one to four USB ports • Managed by a USB host controller • As many as 127 USB devices can be daisy changed together using USB devices

33. USB Ports

34. USB Ports

35. USB Ports

36. Installing a USB Device • Requirements • Motherboard or expansion card that provides a USB port • OS that supports USB • USB device • USB device driver • Use Device Manager to verify that USB host controller is installed

37. Using IEEE 1394 Ports • Provides either a 4-pin or 6-pin connector • Uses only one set of system resources • Uses isochronous data transfer • Is hot-pluggable

38. IEEE 1394 Ports

39. IEEE 1394 Ports

40. Using PCI Expansion Slots • PCI bus runs in sync with CPU • PCI controller manages system resources for all PCI cards • Use Device Manager to determine which IRQ has been assigned to a PCI device • PCI bus IRQ steering can help solve problem of not having enough IRQs to support all devices

41. PCI Expansion Slots

43. MCA and EISA Buses • Microchannel Architecture (MCA) bus • First 32-bit bus for PCs • EISA (Extended ISA) bus • Designed to compete with MCA bus

44. Using ISA Expansion Slots • Configuration is not automated • ISA bus does not manage system resources, as do USB and PCI bus masters • ISA device must request system resources at startup

45. Installing Legacy Hardware • Solving problems with legacy hardware • Solving problems with legacy drivers

46. Keyboards • Technologies in the way the keys make contact • Foil contact • Metal contact

47. Keyboard Connectors • PS/2 connector • DIN connector • USB port • Wireless connection • Requires a driver

48. A Keyboard Adapter

49. Pinouts for Keyboard Connectors

50. Troubleshooting Keyboards • A few keys don’t work • Keyboard does not work at all • Key continues to repeat after being released • Keys produce wrong characters • Major spills on keyboard