Serial, Parallel and other IO Interfaces

1
Serial, Parallel and other I/O Interfaces

• CIS 145
• Microprocessor Servicing
• Kelvin Kempfer

2
Outline

• Standard I/O Ports
• Parallel Ports
• Serial Ports
• USB
• PS/2

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Standard I/O Ports

• VGA (Video Graphics Array)
• Parallel Ports
• Used for local printers
• Serial Ports
• Console connection
• Game Port
• Joystick
• PS/2
• Keyboard and mouse
• USB
• Multiple Peripherals

4
Standard I/O Ports
D-Shell Connectors

• Female Receptors
• VGA
• Parallel
• Game

• Male Receptors
• Serial Ports

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Standard I/O Ports

• Female Ports
• Pin Arrangement
• VGA - 3 rows each having 5 openings
• MGA CGA - 2 rows each having 5 openings
• Parallel - 2 rows 1 row of 13 and 1 row of 12
• Game Port - 2 rows 1 row of 8 and 1 row of 7

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Standard I/O Ports

• Serial Ports
• Male Ports
• Pin Arrangement
• 25-pin - 1 row of 13 and 1 row of 12
• 9-pin - 1 row of 5 and 1 row of 4

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Parallel Ports

• Peripheral Devices
• Operation
• IBM Version
• Faster and Better Parallel Ports
• LPT Handles

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Peripheral Devices

• Printers
• X-Y Plotters
• Computer-to-computer systems
• Removable disk backup systems
• Optical scanners

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Operation

• Address on the bus Port address
• Ports Address Setting
• jumpers
• DIP switches
• Firmware/PnP

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Operation

• Data-out
• microprocessor places a data word on the data bus
• sends an I/O write signal to the port
• Data available strobe
• port applies to the peripheral
• Data-in
• transfers data

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IBM Version

• Introduced 1987 (PS/2)
• Bi-directional parallel port
• Commonly found in PC-compatible systems
• 8-bit parallel data and 9 I/O control lines

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Faster and Better Parallel Ports

• Enhanced Parallel Port (EPP)
• Fast Mode Parallel Port
• IEEE 1284 standard
• common on IBM machines
• Enhanced Capabilities Port (ECP)
• requires special hardware logic
• IEEE 1284 standard
• ECP can be turned into EPP or standard
  unidirectional parallel ports via BIOS

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IEEE 1284

• Defines the electrical signaling behavior
• Standardizing the behavior between a PC and an
  attached device
• hardware and line control-only standard
• Allows much higher throughput in a connection
• printer cable uses twisted-pair technology
• A new connector (1284 Type C)
• found on HPs printer line

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LPT Handles

• LPT1
• address 3BCh or 378h
• IRQ7
• Parallel ports located on video display cards are
  normally assigned 3BCh

• LPT2
• address 378h or 278h
• IRQ5

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Serial Ports

• Serial Transmission Modes
• Serial Interface ICs
• Serial Standards
• DOS Serial Port Names

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Serial Transmission Modes

• Parallel-in, Serial out (PISO)
• Serial-in, Parallel out (SIPO)

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Serial Transmission Modes

• Synchronously
• in conjunction with a synchronizing clock pulse
• Asynchronously
• without an accompanying clock pulse

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Serial Interface ICs

• Asynchronous
• Asynchronous Communication Interface Adapters
  (ACIAs)
• Universal Asynchronous Receiver/Transmitters
  (UARTs)

• Synchronous
• Universal Synchronous/Asynchronous
  Receiver/Transmitters ( USARTs)

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DOS Serial Port Names

• Either RS-232 port may be designated as COM1,
  COM2, COM3, COM4
• COM1 COM2 COM3 COM4
• 3F8h 2F8h 3E8h 2E8h
• IRQ4 IRQ3 IRQ4 IRQ3

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USB Ports

• Allows for hot-swapping and is hot-pluggable
• Version 2 allows for up to 480Mb/s
• Backward compatible with slower USB devices
• USB host controller
• As many as 127 USB devices
• Hub
• Windows 95 OSR 2.1 first to support
• Windows NT does not

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IEEE 1394

• Commonly know as FireWire and i.Link
• Supports speeds as high as 1.2Gbps
• Likely to replace SCSI
• Uses Isochronous data transfer
• Information transferred without breaks
• Windows 98, 2k and XP support IEEE 1394

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USB Compared to FireWire

• IEEE-1394
• (a.k.a. i.linkFireWire) USB
  1.1 USB 2.0
• PC-host required No Yes Yes
• Max. of devices 63 127 127
• Hot-swappable Yes Yes Yes
• Max. Cable length 4.5m 5m 5m
• Transfer rate 200Mbps 12Mbps 480Mbps
• Future trans. rates 400Mbps None None
• 800Mbps
• 1Gbps
• Typical devices DV camcorders keyboards
  all USB 1.1 devices
• digital cameras mice digital
  cameras
• HDTV joysticks camcorders
• high-speed stuff printers high
  speed stuff

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Keyboards/Pointers

• PS/2
• Sometimes called mini-DIN
• 6 pins
• DIN connector
• 5 pins
• AT Keyboard Port
• USB port
• Wireless connection