lecture7 Input Output and Secondary Memory 2013

1 supports up to 127 devices connected to the same

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Unformatted text preview: ed via serial are generally much slower than those connected by parallel. • Serial is convenient, relatively inexpensive and getting faster all of the time. • The current serial standard for peripherals is called USB 2.0 USB 2.0 • Max transfer speed of 400Mbps (Megabits per second), 40 times faster than the predecessor USB 1.1 • Supports up to 127 devices connected to the same controller chip! • A USB cable can be 5 meters long without causing any performance problems • USB has become the ubiquitous serial connection standard for practically every external PC peripheral IEEE 1394, aka Firewire • Another high speed serial bus in wide use is the Firewire bus, first introduced by Apple • Similar in performance to USB 2.0 • Designed primarily for video devices such as camcorders, digital TVs, DVD devices and VCRs • Many PCs today also include Firewire for use with Video authoring software and downloading video onto your computer USB 3.0! • Standard introduced in 2008 • Up to 5 Gigabits per second! • 10 times faster than USB 2.0 Clocking Data • Both serial and parallel busses transfer data using a clock signal that ensures that data is sent and received at certain times based on the clock speed. • Without the clock, data transfers would be less reliable given the variation in cable length and other environmental factors Wireless I/O • Wifi: Wireless local area network (LAN) technology that uses Internet Protocol to transfer data between devices. Latest generation (n) operates at >100 megabits/second and has an indoor range of about 150 ft. • Bluetooth: Personal area network (PAN) Very low power with range of <20 ft in most applications and speeds of 80 kilobits/second I/O Example using a car climate control system Fan Compressor Touchscree n On/Off Switch, Temperature, Humidity Questions?...
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