Part VI Input/Output and Interfacing Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 1 About This Presentation This presentation is intended to support the use of the textbook Computer Architecture: From Microprocessors to Supercomputers, Oxford University Press, 2005, ISBN 0-19-515455-X. It is updated regularly by the author as part of his teaching of the upper-division course ECE 154, Introduction to Computer Architecture, at the University of California, Santa Barbara. Instructors can use these slides freely in classroom teaching and for other educational purposes. Any other use is strictly prohibited. © Behrooz Parhami Edition Released Revised Revised Revised Revised First July 2003 July 2004 July 2005 Mar. 2007 Mar. 2008 Mar. 2009 Feb. 2011 Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 2 VI Input/Output and Interfacing Effective computer design & use requires awareness of: • I/O device types, technologies, and performance • Interaction of I/O with memory and CPU • Automatic data collection and device actuation Topics in This Part Chapter 21 Input/Output Devices Chapter 22 Input/Output Programming Chapter 23 Buses, Links, and Interfacing Chapter 24 Context Switching and Interrupts Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 3 21 Input/Output Devices Learn about input and output devices as categorized by: • Type of data presentation or recording • Data rate, which influences interaction with system Topics in This Chapter 21.1 Input/Output Devices and Controllers 21.2 Keyboard and Mouse 21.3 Visual Display Units 21.4 Hard-Copy Input/Output Devices 21.5 Other Input/Output Devices 21.6 Networking of Input/Output Devices Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 4 Section 21.1: Introduction Section 21.3 Section 21.4 Section 21.2 Section 21.5: Other devices Section 21.6: Networked I/O Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 5 21.1 Input/Output Devices and Controllers Table 3.3 Some input, output, and two-way I/O devices. Input type Prime examples Other examples Data rate (b/s) Main uses Symbol Keyboard, keypad Music note, OCR 10s Ubiquitous Position Mouse, touchpad Stick, wheel, glove 100s Ubiquitous Identity Barcode reader Badge, fingerprint 100s Sales, security Sensory Touch, motion, light Scent, brain signal 100s Control, security Audio Microphone Phone, radio, tape 1000s Ubiquitous Image Scanner, camera Graphic tablet 1000s-106s Photos, publishing Video Camcorder, DVD VCR, TV cable 1000s-109s Entertainment Output type Prime examples Other examples Data rate (b/s) Main uses Symbol LCD line segments LED, status light 10s Ubiquitous Position Stepper motor Robotic motion 100s Ubiquitous Warning Buzzer, bell, siren Flashing light A few Safety, security Sensory Braille text Scent, brain stimulus 100s Personal assistance Audio Speaker, audiotape Voice synthesizer 1000s Ubiquitous Image Monitor, printer Plotter, microfilm 1000s Ubiquitous Video Monitor, TV screen Film/video recorder 1000s-109s Entertainment Two-way I/O Prime examples Other examples Data rate (b/s) Main uses Mass storage Hard/floppy disk CD, tape, archive 106s Ubiquitous Network Modem, fax, LAN Cable, DSL, ATM 1000s-109s Ubiquitous Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 6 Simple Organization for Input/Output Interrupts CPU Main memory Cache System bus I/O controller I/O controller I/O controller Graphics Disk Disk Network display Figure 21.1 Input/output via a single common bus. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 7 I/O Organization for Greater Performance Interrupts CPU Main memory Cache Memory bus Proprietary Bus Bus AGP adapter PCI bus adapter Intermediate Standard buses / ports Bus I/O bus adapter I/O controller I/O controller I/O controller I/O controller Graphics display Network Disk Disk CD/DVD Figure 21.2 Input/output via intermediate and dedicated I/O buses (to be explained in Chapter 23). Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 8 21.2 Keyboard and Mouse Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 9 Keyboard Switches and Encoding Key cap c d e f Spring 8 9 a b (a) Mechanical switch with a plunger 4 5 6 7 Conductor-coated membrane Contacts 0 1 2 3 (b) Membrane switch (c) Logical arrangement of keys Figure 21.3 Two mechanical switch designs and the logical layout of a hex keypad. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 10 Projection Virtual Keyboard Hardware: A tiny laser device projects the image of a full-size keyboard on any surface Software: Emulates a real keyboard, even clicking key sounds Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 11 Pointing Devices Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 12 How a Mouse Works y roller x roller Mouse pad y axis Photosensor detects Ball touching the rollers crossing of grid lines x axis rotates them via friction (a) Mechanical mouse (b) Optical mouse Figure 21.4 Mechanical and simple optical mice. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 13 21.3 Visual Display Units Deflection coils Electron beam ≅ 1K lines Pixel info: Electron brightness, gun color, etc. y x Sensitive ≅ 1K pixels Frame buffer screen per line (a) Image formation on a CRT (b) Data defining the image Figure 21.5 CRT display unit and image storage in frame buffer. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 14 How Color CRT Displays Work R G B R G B R G B R G B R G B R G B Direction of Direction of Direction of blue beam green beam red beam Shadow mask R G B Faceplate (a) The RGB color stripes (b) Use of shadow mask Figure 21.6 The RGB color scheme of modern CRT displays. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 15 Encoding Colors in RGB Format Besides hue, saturation is used to affect the color’s appearance (high saturation at the top, low saturation at the bottom) Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 16 Flat-Panel Displays Colum n puls es Colum n puls es Row lines Address pulse Column (data) lines Column (data) lines (a) Passive display (b) Active display Figure 21.7 Passive and active LCD displays. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 17 Flexible Display Devices Paper-thin tablet-size display unit by E Ink Sony organic light-emitting diode (OLED) flexible display Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 18 Other Display Technologies Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 19 21.4 Hard-Copy Input/Output Devices Document (face down) Detector: Filters Lens charge-coupled device (CCD) Mirror Light beam A/D converter Light source Scanning software Mirror Image file Figure 21.8 Scanning mechanism for hard-copy input. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 20 Character Formation by Dot Matrices oooooooooooooo ooooooooooooooooo oo oooo oo ooo oo oo oo oo oo oo oo oo oo oo ooooooooo oo o o oo oo oo o oo oo oo o o oo oo o o oo oo o o oo oo ooooo o o oo oo o o o o oo oo o o o o oo oo o o o o oo oo o o o o oo oo o o o o oo oo o o o o oo oo o o o o oo oo ooooo o o oo oo o o oo oo o o oo oo oooooooooooooo oo oo ooooooooooooooooo o o oo oooo oo ooo oo oo oo oo oo oo oo oo o oo oo oo oo oo oo o oo oo ooooo oo oo oo o oo oo oo oo o oo oo o oo oo oo o o oo oo ooooooooo o oo oo o oo oo o oo oo oo oo o oo oo o oo oo o oo oo o oo oo o oo oo oo oo o oo oo o oo oo o oo oo o oo oo oo oo oo oo oo oo oo oo oo o ooooo oo oo oo oo oo oo oo oo oo oo oo oo oo ooo oo oo oo oooo ooooooooooooooooo oooooooooooooo Same dot matrix size, oo ooo oo oooo but with greater resolution ooooooooooooooooo oooooooooooooo Figure 21.9 Forming the letter “D” via dot matrices of varying sizes. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 21 Simulating Intensity Levels via Dithering Forming five gray levels on a device that supports only black and white (e.g., ink-jet or laser printer) Using the dithering patterns above on each of three colors forms 5 × 5 × 5 = 125 different colors Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 22 Simple Dot-Matrix Printer Mechanism Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 23 Common Hard-Copy Output Devices Cleaning of excess toner Corona wire Sheet of for charging paper Fusing of toner Paper Rotating movement Heater drum Print head assembly Light from Rollers optical Print system head Ink Print head Toner supply movement Sheet of Ink droplet paper (a) Ink jet printing (b) Laser printing Figure 21.10 Ink-jet and laser printers. Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 24 How Color Printers Work Red Green The RGB scheme of color monitors is additive: various amounts of the three primary colors are added to form a desired color Blue Absence of green Cyan Magenta The CMY scheme of color printers is subtractive: various amounts of the three primary colors are removed from white to form a desired color To produce a more satisfactory shade of black, Yellow the CMYK scheme is often used (K = black) Feb. 2011 Computer Architecture, Input/Output and Interfacing Slide 25 The CMYK Printing Process Illusion of full color created with CMYK dots Feb.