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Parallel Connections

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Host sends important data (a print job, for example) to device. ... 'PCMCIA card' image: http://upload.wikimedia.org/wikipedia/commons/b/b1 ... – PowerPoint PPT presentation

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Title: Parallel Connections


1
Parallel Connections
  • This presentation will probably involve audience
    discussion, which will create action items. Use
    PowerPoint to keep track of these action items
    during your presentation
  • In Slide Show, click on the right mouse button
  • Select Meeting Minder
  • Select the Action Items tab
  • Type in action items as they come up
  • Click OK to dismiss this box
  • This will automatically create an Action Item
    slide at the end of your presentation with your
    points entered.
  • Michael Fromwiller
  • CS 147 Spring 08
  • Dr. Sin-Min Lee

2
Parallel Interfaces
  • Buses transfer data inside computers.
  • Monitors, printers, and other devices do not
    connect to the system bus.
  • External devices connect to interface circuits
    which are used to manage the connection.
  • Proper connections require the ability to send
    and receive data.

3
Centronics Printer Interface
  • Multi-wire parallel link.
  • Transfers 8 bits of ASCII code simultaneously.
  • Typical speed 100 kbytes/sec over10 meters.
  • Not considered a bus
  • Does not offer support for more than two devices.

4
Centronics Printer Interface
  • Up to 8x faster than serial connections! but
    suffers from skew
  • Differences in wire resistances
  • Lots of wires
  • Signal degradation, delays, and
  • data corruption. Yuck.

Low Skew
High Skew
5
Centronics Printer Interface
  • Three standards for this interface

Mode Name Speed I/O Controller
SPP Standard Parallel Port 100 kbytes/s Output Software Controlled
EPP Enhanced Parallel Port 1 Mbytes/s Output Input Hardware Controlled
ECP Extended Capability Port 5 Mbytes/s Output Input DMA w/ FIFO
6
Standard Parallel Port (SPP)
  • Software handles connection (slow)
  • Host sends important data (a print job, for
    example) to device.
  • Device sends status messages to the host
  • Accepting data
  • Busy, try again later
  • Out of paper
  • Error found
  • Typical setup between devices for asynchronous
    handshaking.

7
EPP and ECP Modes
  • Both offer bi-directional lines for data
    communication between device and host.
  • Important for Plug-and-Play process.
  • Hardware handles data transmission
  • Software writes data to port buffer
  • Hardware handles the rest (fast!)

8
SCSI - Small Computer Systems Interface
  • Fast asynchronous byte-wide bus(5 Mbytes/sec)
    connecting up to 8 devices
  • A secondary bus which relieves the traffic from
    the main bus.
  • Intended for
  • Hard disk drives
  • CD-ROM drives
  • Tape units

9
SCSI - Small Computer Systems Interface
  • Variations of SCSI standards
  • Fast SCSI
  • (10 Mbytes/sec synchronous transfer mode)
  • Wide SCSI
  • (40 Mbytes/sec with 32 bit data bus)
  • Useful for
  • Multiple computers with shared drives
  • Multiple CD-ROM burners for mass production
  • Tape drives

10
IDE Intelligent Drive Electronics
  • Simplified version of the ISA bus.
  • Standard was quickly accepted.
  • Used by cheapest hard disk drives
  • Used by most common hard disk drives
  • Ribbon connections support two devices
  • Master
  • Slave.
  • Plugs directly into the AT bus.

11
AT / ISA bus
  • Appeared around the time the Intel 8088 processor
    came out.
  • Ran at 4.77 Mhz
  • Later topped off at 8.33 Mhz
  • Faster processors would wait till the ISA bus was
    finished, affecting speed.
  • Pentium CPUs made the speed difference clear.
  • Extended ISA (EISA) clocked at 33 Mhz, but was
    overshadowed by the new PCI bus.

12
PCI Peripheral Component Interconnection
  • PCI bus isolated from main bus by a bridge
    device, such as the i82443.
  • North Bridge
  • Handles PCI components
  • South Bridge
  • PCI to ISA bridging device, such as the i82371
  • Development of the mini-PCI was brought about by
    laptop computers, for PC add-ons.

13
PCI Peripheral Component Interconnection
  • PCI bus operates in two modes
  • Multiplexed Mode
  • A single 32 bit bus that is shared by address and
    data information.
  • Increased bus width, but reduced data rate.
  • Burst Mode
  • Same idea as EDO DRAM. After one address has been
    sent, several data items follow in quick
    succession.
  • Bridge is capable of assembling these packets
    of data and bursting it to the PCI bus when ready.

14
Plug-and-Play
  • Introduced by Microsoft.
  • Main purposes
  • Allow computer to auto-configure hardware.
  • Simplify hardware installation.
  • Make the PC more user friendly
  • Released with Windows 95.
  • Fully supported by Windows 2000/XP.

15
PCMCIA Personal Computer Memory Card
International Association
  • Credit card sized
  • Originally intended for memory expansion for
    laptops.
  • Designed for hot swapping. No need to turn off
    or reboot laptops. Just pop and go!
  • Manufacturers took it a lot further
  • Modems and Ethernet interfaces
  • Video cards
  • Parallel ports
  • Disk drives
  • Pretty much anything!

16
Sources
  • All information from this presentation can be
    found inComputer Systems Architecture A
    Networking ApproachRob Williams. Chapter 11
  • Low and high skew images
  • http//www.spectra-strip.amphenol.com
  • Parallel printer cable image
  • http//www.nuggetlab.com/comptia_files/equipment/
    cable_Parallel20Cable20showing2025-pin20end.jp
    g
  • SCSI ribbon cable image
  • http//www.qvs.com/prodimages/SCU160-4T_LR.jpg
  • IDE ribbon cable image
  • http//www.cable-house.com/images/cables/internal
    20cables/ide_ata133_ribbon_cable.jpg
  • Granny with computer image
  • http//www.boston.com/business/blog/filter/momtech
    support.jpg
  • PCMCIA card image
  • http//upload.wikimedia.org/wikipedia/commons/b/b1
    /Pcmcia-type-ii-and-iii.jpg
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