Supporting I/O Supporting I/O DevicesDevices

Basic Principles of Basic Principles of Peripheral Peripheral InstallationsInstallations Both hardware and software must be Both hardware and software must be

installed (hardware is controlled by installed (hardware is controlled by software) software)

Install all levels of softwareInstall all levels of software Device driver must be written specifically Device driver must be written specifically

for the OSfor the OS More than one peripheral device might More than one peripheral device might

attempt to use same resources attempt to use same resources Update drivers, the firmware, or bothUpdate drivers, the firmware, or both

Installation OverviewInstallation Overview

1.1. Install the device (internal or Install the device (internal or external)external)

2.2. Install the device driverInstall the device driver

3.3. Install the application softwareInstall the application software

PortsPorts

Using Ports and Using Ports and Expansion Slots for Add-Expansion Slots for Add-on Deviceon Device PortsPorts

– SerialSerial

– ParallelParallel

– USBUSB

– IEEE 1394IEEE 1394

– SCSISCSI

Expansion slotsExpansion slots

Port SpeedsPort Speeds

Using Serial PortsUsing Serial Ports

Transmit data in single bits (serially)Transmit data in single bits (serially)

Nine or 25 pinsNine or 25 pins

Almost always maleAlmost always male

Originally intended for input and Originally intended for input and output devicesoutput devices

Configured as COM1, COM2, COM3, Configured as COM1, COM2, COM3, or COM4or COM4

Using Serial Ports Using Serial Ports ((continuedcontinued))

Port assignments are made in CMOS Port assignments are made in CMOS setupsetup

Conform to standard interface called Conform to standard interface called RS-232cRS-232c

Data Terminal Equipment (DTE) and Data Terminal Equipment (DTE) and Data Communications Equipment Data Communications Equipment (DCE) designations(DCE) designations

Port ComparisonPort Comparison

Default Port Default Port AssignmentsAssignments

Serial Port Serial Port SpecificationsSpecifications

Null Modem Null Modem ConnectionConnection Enables data transmission Enables data transmission

between two DTE devices without between two DTE devices without the need for modemsthe need for modems

Special cable (null modem cable) Special cable (null modem cable) has several wires cross-connected has several wires cross-connected to simulate modem connectionto simulate modem connection

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

Wire Connections on a Wire Connections on a 25-Pin Null Modem 25-Pin Null Modem Cable Cable

Infrared TransceiversInfrared Transceivers

Use resources of a serial port for Use resources of a serial port for communicationcommunication

Create a virtual infrared serial port and Create a virtual infrared serial port and virtual infrared port for infrared devicesvirtual infrared port for infrared devices

UART logic on the motherboard UART logic on the motherboard controls serial ports on the boardcontrols serial ports on the board

Line-of-sight issueLine-of-sight issue

Using Parallel PortsUsing Parallel Ports Transmit data in parallel, eight bits at a Transmit data in parallel, eight bits at a

timetime

Almost always femaleAlmost always female

Originally intended for printersOriginally intended for printers

Can be configured as LPT1, LPT2, or LPT3Can be configured as LPT1, LPT2, or LPT3

Port assignments are made in CMOS setupPort assignments are made in CMOS setup

Avoid using a cable longer than 15 feet to Avoid using a cable longer than 15 feet to ensure data integrityensure data integrity

Types of Parallel PortsTypes of Parallel Ports

Standard parallel port (SPP)Standard parallel port (SPP)– Allows data to flow in only one directionAllows data to flow in only one direction

– Slowest of the three typesSlowest of the three types

Enhanced Parallel Port (EPP)Enhanced Parallel Port (EPP)– Bi-directionalBi-directional

Extended Capabilities Port (ECP)Extended Capabilities Port (ECP)– Bi-directionalBi-directional

– Uses the DMA channelUses the DMA channel

A Standard Parallel A Standard Parallel PortPort

Configuring Parallel Configuring Parallel PortsPorts Setup can have up to four Setup can have up to four

different settings for parallel portsdifferent settings for parallel ports

Using USB PortsUsing USB Ports

Effortless installation of slow Effortless installation of slow peripheral devicesperipheral devices

Much faster than regular serial ports; Much faster than regular serial ports; use higher-quality cablinguse higher-quality cabling

Easier to manage; eliminate need to Easier to manage; eliminate need to manually resolve resource conflictsmanually resolve resource conflicts

Likely to replace serial and parallel Likely to replace serial and parallel portsports

Using USB Ports Using USB Ports ((continuedcontinued)) Allow for hot-swapping; are hot-Allow for hot-swapping; are hot-

pluggablepluggable

Most current motherboards have one Most current motherboards have one to four USB portsto four USB ports

Managed by a USB host controllerManaged by a USB host controller

As many as 127 USB devices can be As many as 127 USB devices can be daisy-chained together using USB daisy-chained together using USB devicesdevices

USB PortsUSB Ports

USB Host ControllerUSB Host Controller

Requirements for Requirements for Preparing to Install a Preparing to Install a USB DeviceUSB Device Motherboard or expansion card Motherboard or expansion card

that provides a USB portthat provides a USB port

OS that supports USBOS that supports USB

USB deviceUSB device

USB device driverUSB device driver

Installing a USB DeviceInstalling a USB Device

Some devices (eg, printers) require the Some devices (eg, printers) require the device to be plugged in before installationdevice to be plugged in before installation

Some devices (eg, scanners) require the Some devices (eg, scanners) require the driver to be installed before the device is driver to be installed before the device is plugged inplugged in

Using Device Manager, verify that USB Using Device Manager, verify that USB controller is installed and working properlycontroller is installed and working properly

Using IEEE 1394 PortsUsing IEEE 1394 Ports

Transmit data serially; faster than USBTransmit data serially; faster than USB Likely to replace SCSI for high-volume, Likely to replace SCSI for high-volume,

multimedia external devicesmultimedia external devices Provide either a 4-pin or 6-pin connectorProvide either a 4-pin or 6-pin connector Hot-pluggableHot-pluggable

– Can be daisy-chained together and managed Can be daisy-chained together and managed by a host controller using one set of system by a host controller using one set of system resourcesresources

Use isochronous data transferUse isochronous data transferIsochronous transfers involve large streams of data. This format is used to move continuous, real-time data streams such as voice or video. Data delivery rates are predetermined and correspond to the sampling rate o the device.

IEEE 1394 Port IEEE 1394 Port StandardsStandards IEEE 1394AIEEE 1394A

– Supports data speeds up to 1.2 GbpsSupports data speeds up to 1.2 Gbps

– Allows for cable lengths up to 15 feetAllows for cable lengths up to 15 feet

IEEE 1394BIEEE 1394B

– Supports speeds up to 3.2 GbpsSupports speeds up to 3.2 Gbps

– Allows for cable length up to 328 feet Allows for cable length up to 328 feet

IEEE 1394 Cable IEEE 1394 Cable ConnectionsConnections

Using IEEE 1394 PortsUsing IEEE 1394 Ports

KeyboardsKeyboards

Traditional straight design or ergonomic Traditional straight design or ergonomic designdesign

Two technologies for keys making Two technologies for keys making contactcontact

– Foil contactFoil contact

– Metal contactMetal contact

Installing keyboardsInstalling keyboards

Keyboard ConnectorsKeyboard Connectors

PS/2 connector (or mini-DIN)PS/2 connector (or mini-DIN)

– Small, round, with six pinsSmall, round, with six pins

DIN (Deutsche Industrie Norm) DIN (Deutsche Industrie Norm) connectorconnector

– Round with five pinsRound with five pins

USB portUSB port

Wireless connectionWireless connection

– Requires a driverRequires a driver

Keyboard Connectors Keyboard Connectors ((continuedcontinued) )

Pinouts for Keyboard Pinouts for Keyboard ConnectorsConnectors

Pinouts for Keyboard Pinouts for Keyboard ConnectorsConnectors

You'll notice a few things about the table. First, there are only four actual signals used in the standard keyboard interface; the extra pins on both types of connector are not used

(This mismatch means that the connectors were chosen either from existing designs to save development costs, or that room was left for future expansion that was never used. Both occur commonly in the PC industry.)

A Keyboard AdapterA Keyboard Adapter

Since the signals are the same for the two types of connector--they just use different pins. This means that simple mechanical adapters can be made to convert between the two. These adapters let a keyboard that terminates in a large connector work on a system that requires a small connector, and vice-versa.

Troubleshooting Troubleshooting KeyboardsKeyboards A few keys don’t workA few keys don’t work

Keyboard does not work at allKeyboard does not work at all

Key continues to repeat after being Key continues to repeat after being releasedreleased

Keys produce the wrong charactersKeys produce the wrong characters

Major spills on the keyboardMajor spills on the keyboard

Pointing DevicesPointing Devices

How a Wheel Mouse How a Wheel Mouse Works Works

How a Mouse ConnectsHow a Mouse Connectsto the Computerto the Computer Dedicated round mouse port Dedicated round mouse port

(motherboard mouse or PS/2-compatible (motherboard mouse or PS/2-compatible mouse)mouse)

Mouse bus card (bus mouse)Mouse bus card (bus mouse)

Serial port (serial mouse)Serial port (serial mouse)

USB portUSB port

Y-connection with the keyboardY-connection with the keyboard

Cordless technologyCordless technology

Pointing DevicesPointing Devices

Touch screensTouch screens

Other pointing devicesOther pointing devices

– TrackballsTrackballs

– Touch padsTouch pads

Troubleshooting a Troubleshooting a MouseMouse Check mouse port connectionCheck mouse port connection

Check for dust or dirt; reboot PCCheck for dust or dirt; reboot PC

Try new mouseTry new mouse

Uninstall and reinstall mouse driver; reboot Uninstall and reinstall mouse driver; reboot PCPC

Reboot PC and select logged option from Reboot PC and select logged option from startup menu to create Bootlog.exe filestartup menu to create Bootlog.exe file

– Continue to boot and check log for errorsContinue to boot and check log for errors

Other DevicesOther Devices

Scanners Web Cameras Biometric Devices Bar Code Readers Touch Screens