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CIS 212 Microcomputer Architecture Day 18

CIS 212 Microcomputer Architecture Day 18. Rhys Eric Rosholt. Office: Office Phone: Web Site: Email Address:. Gillet Hall - Room 304 718-960-8663 http://comet.lehman.cuny.edu/rosholt/ rhys.rosholt @ lehman.cuny.edu. Chapter 7 Input/Output Technology. Chapter 7 Input/Output Technology.

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CIS 212 Microcomputer Architecture Day 18

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  1. CIS 212MicrocomputerArchitectureDay 18 Rhys Eric Rosholt Office: Office Phone: Web Site: Email Address: Gillet Hall - Room 304 718-960-8663 http://comet.lehman.cuny.edu/rosholt/ rhys.rosholt @ lehman.cuny.edu

  2. Chapter 7Input/Output Technology

  3. Chapter 7Input/Output Technology Chapter Outline Basic Concepts of Print and Display Technology Focus – Adobe Postscript and Portable Document Format Video Display Printers Manual Input Devices Optical Input Devices Audio I/O Devices

  4. Chapter Goals • Describe common concepts of text and image representation and display including digital representation of grayscale and color, bitmaps, and image compression techniques • Describe the characteristics and implementation technology of video display devices • List and describe the three predominant manual input technologies • Understand printer characteristics and technology • Describe various types of optical input devices including mark sensors, bar code readers, scanners, and digital cameras • Identify the characteristics of audio I/O devices, and explain how they operate

  5. Chapter 7Input/Output Technology

  6. Colors by Electromagnetic Wavelength and Frequency

  7. Color CodingRGBOne byte for each basic color

  8. Video Monitors • Separate from keyboards • Common types • Cathode ray tubes (CRTs) • Liquid crystal displays (LCDs) • Plasma displays

  9. CRT • Enclosed vacuum tube; electron beam is focused toward front surface of the tube, which is coated in phosphor • Technology relatively old; has disadvantages • Physical size and weight • Power consumption

  10. LCD • Contains matrix of liquid crystals sandwiched between two polarizing filter panels • Active and passive matrix displays • Manufactured with thin film transistor (TFT) technology • Compared with CRTs • Less contrast • Reduced size, weight, and power consumption • Higher cost

  11. How an LCD works

  12. Plasma Displays • Combine elements of CRT and LCD technology • Flat panel, active matrix devices • Actively generate colored light near surface of the display; good brightness and viewing • Require more power than LCDs, less than CRTs • Shortcomings • Limited operational lifetime • Larger pixel size reduces comparative image quality when viewed from short distances

  13. Plasma Displays Plasma displays have no backlight and no color filters; each pixel contains a gas that emits ultraviolet light when electricity is applied.

  14. Printers

  15. Printer Communication • Impact printers • ASCII or Unicode characters • Inkjet and laser printers • Use pixels as fundamental output unit • Have relatively large buffers • IDLs are commonly used to improve printer performance

  16. Dot Matrix Printers

  17. Daisy Wheel Printers

  18. Inkjet Printers • Most common printing technology • Prints with liquid ink placed directly onto paper • Uses mechanical movement or heat to force ink out of nozzle • Paper is drawn past moving print head • Resolution is up to 600 dpi

  19. Inkjet Printers An inkjet printer has disposable print cartridges that contain ink reservoirs, a matrix of ink nozzles, and electrical wiring and contact points.

  20. Lasar Printers

  21. Lasar Printers Laser printers operate with an electrical charge and the attraction of ink to that electrical charge.

  22. Lasar Printers

  23. Lasar Printers

  24. Lasar Printers

  25. Plotters • Printers that generate line drawings on wide sheets or rolls of paper • Use inkjet technology • Ideal for blueprints and other engineering drawings • Also called large format printers

  26. Manual Input Devices

  27. Keyboards • Translate keystrokes directly into electrical signals • Generate bit stream outputs (scan code) with a keyboard controller • Can connect to computer in various ways(e.g., PS/2, USB, wireless)

  28. Pointing Devices • Mouse • Trackball • Joystick • Input pads (e.g., digitizer tablet) • Infrared detector • Photosensor • Pressure-sensitive pad

  29. Optical Input Devices • Detect light reflected off a printed surface or object into a photosensor • Categories • Mark and pattern sensors • Image capture devices

  30. Mark Sensors and Bar-Code Scanners • Mark sensor • Scans for light or dark marks at specific locations on a page (e.g., standardized multiple-choice test) • Bar code scanner • Detects specific patterns of vertical bars of varying thickness and spacing • Typically used to track large numbers of inventory items

  31. PDF417 Bar Code Advanced scanning technology can now read two-dimensional bar codes.

  32. Optical Scanners • Generate bitmap representations of printed images • Bright white light shines on the page; reflected light is detected by an array of photosensors • Optical character recognition (OCR) devices • Combine optical scanning technology with intelligent interpretation of bitmap content

  33. Next ClassThursdayApril 5, 2012 Rhys Eric Rosholt Office: Office Phone: Web Site: Email Address: Gillet Hall - Room 304 718-960-8663 http://comet.lehman.cuny.edu/rosholt/ rhys.rosholt @ lehman.cuny.edu

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