Peripheral Interfaces

list of available interfaces

1.      Serial 2.      Parallel3.      ATA/IDE 4.      Serial ATA5.      SCSI6.      USB7.      Firewire8.      Infrared serial9.      Joystick port

The serial port• The serial port is a low-speed peripherals port designed

for devices that don't need to transfer a lot of data, like mice or modems.

• The port is "serial" because data bits are transmitted one at a time.

• The international standard for serial ports is called RS-232.

• Serial ports are still used for external modems, PDAs/palmtops, and occasionally mice or game controllers, but these devices are rapidly converting to the newer Universal Serial Bus (USB).

• If your computer supports USB, a USB version of a device is highly preferable to the serial port version for long-term compatibility.

The serial port

The serial port

The serial port, UARTs

Chip# speed8250 9600 bps16550 115 kbps16550 230 kbps16750 460 kbps

• You can find out what UART is installed in your PC by running MSD.EXE in the DOS mode.

• You can find MSD.EXE in Win98/Me/2000 CD-ROM /tools/ folder.

• Try shareware version of SiSoft Sandra - http://www.sisoftware.co.uk/sandra/html/dload.htm

Enhanced Serial Port (ESP) or Super ESP

The serial port Configuaration

The parallel port• The parallel port is the wide 25-pin port on the back of

the computer which is used to communicate with printers and some other peripheral devices.

• There are several different parallel port standards, including

– SPP (standard parallel port), – Bidirectional, – EPP ("enhanced parallel port") and – ECP ("extended capabilities port").

• Most modern computers can support any of these standards via a user-selectable option in the BIOS setup.

• For maximum compatibility, always set the parallel port standard to match the standards supported by your devices, and never attach more than two devices to the same parallel port.

IEEE 1284, parallel port standard

The parallel port

parallel port types

PS/2 type parallel port• Bidirectional type is also known as PS/2 type or

Extended type.

IDE, Integrated Drive Electronics

• IDE stands for Integrated Drive Electronics. • Most consumer storage devices, like hard disks

and CD-ROMs, use the IDE interface to communicate with the computer.

• PC compatible computers typically have two IDE interface controllers, and each controller can support two devices.

• Storage product manufacturers have confused matters by trademarking their own names for the IDE interface, calling it ATA, UDMA, or EIDE.

• Although they may differ in performance details, they are all intercompatible.

IDE/ATA

• Usually these devices connect to the computer through an Integrated Drive Electronics (IDE) interface.

• Essentially, an IDE interface is a standard way for a storage device to connect to a computer.

• IDE is actually not the true technical name for the interface standard.

• The original name, AT Attachment (ATA), signified that the interface was initially developed for the IBM AT computer.

IDE

• Also Known As: ATA, UDMA, EIDE, UDMA/33, ATA/66, ATA/100, ATAPI

ATA generations

ATA-1 8.33 MB/s

ATA-2 16.67 MB/s

ATA-3 16.67 MB/s

ATA/ATAPI-4, Ultra-ATA/33 33 MB/s UDMA

ATA/ATAPI-5, Ultra-ATA/66 66 MB/s UDMA

ATA/ATAPI-6, ATA/100 100 MB/s UDMA

ATA generations

ATAPI• ATA-4: Probably the two biggest additions to the standard in this version

are Ultra DMA support and the integration of the AT Attachment Program Interface (ATAPI) standard.

• ATAPI provides a common interface for CD-ROM drives, tape backup drives and other removable storage devices.

• Before ATA-4, ATAPI was a completely separate standard.

• With the inclusion of ATAPI, ATA-4 immediately improved the removable media support of ATA.

• Ultra DMA increased the DMA transfer rate from ATA-2's 16.67 MB/sec to 33.33 MB/sec.

• In addition to the existing cable that uses 40 pins and 40 conductors (wires), this version introduces a cable that has 80 conductors.

• The other 40 conductors are ground wires interspersed between the standard 40 conductors to improve signal quality.

• ATA-4 is also known as Ultra DMA, Ultra ATA and Ultra ATA/33.

ATAPI

• ATAPI stands for ATA Packet Interface. • It's a variation on the IDE (also called

ATA) interface used for hard disks, which is specially designed to accomodate removable media devices like CD-ROMs, DVD-ROMs, CD writers and tape drives.

ATA Connectors and Cables

ATA generations

ATA generations

ATA generations

ATA-1 8.33 MB/s

ATA-2 16.67 MB/s

ATA-3 16.67 MB/s

ATA/ATAPI-4, Ultra-ATA/33 33 MB/s UDMA

ATA/ATAPI-5, Ultra-ATA/66 66 MB/s UDMA

ATA/ATAPI-6, ATA/100 100 MB/s UDMA

Serial ATA• High Speed Serialized AT Attachment

Serial ATA• http://www.explosivelabs.com/articles/sata/

Demultiplexing

Serial ATA Connectors

Serial ATA Connectors

• (a) device signal plug segment or connector;

• (b) device power plug segment or connector;

• (c) signal cable receptacle connector, to be mated with (a);

• (d) power cable receptacle connector, to be mated with (b);

• (e) signal cable receptacle connector, to be mated with (f), the host signal plug connector;

• (g) host receptacle connector mating directly with device plug connector (a) & (b).

• Ref: Serial ATA 1.0 gold.pdf

SATA Signal Cable and Connector

SATA Signal Direct Connector

SATA Generations

Parallel ATA vs. Serial ATA

Parallel ATA Serial ATA

Bandwidth 100/133 MB/Secs 150/300/600 MB/Secs

Volts 5V 250mV

Pins 40 7

Length Limitation 18 inch (45.72cm) 1 meter (100cm)

Cable Wide Thin

Ventilation Bad Good

Peer-to-Peer No Yes

SCSI, Small Computer Systems Interface• It is a high-speed peripherals expansion port which

provides support for up to 7 devices on a single connector.

• SCSI is a complex and powerful standard; because of its high bandwidth, it can handle all sorts of devices including hard disks, CD-RW, scanners, removable drives, etc.

• A few computers come with SCSI built-in, but it can be added with a modestly priced PCI card.

• SCSI is comparable to the IDE, USB and parallel port standards, but it is more flexible and more capable than any one of them.

• Only Firewire (IEEE 1394) offers comparable performance.

SCSI Types, Data transfer rates & Cables

SCSI Types, Data transfer rates & Cables

LVD - Low Voltage Differential signaling; HVD - High voltage Differential signaling

SCSI, Symbols

SCSI, Low and High Density 50-pin Connectors

SCSI, High density 68 & 80-pin Connectors

DB-25 SCSI Connector

Cross Section of typical SCSI Cable

SCSI Terminators

SCSI ID Settings 0 ~ 7

SCSI Daisy chain connection: First & last device must be terminated

External SCSI Device Terminator

Internal SCSI Device Terminator

USB & Firewire

USB

• USB stands for Universal Serial Bus, a new standard for connecting external devices like mice, keyboards, scanners and printers.

• USB offers many benefits over traditional connection method, including thinner and cheaper cables, greater expandability (with the addition of a USB hub, a single USB controller can handle up to 125 devices) and greater speed.

• To use USB, your computer needs integrated USB ports or a USB expansion card and Windows 98; Mac users require a Mac with USB and MacOS 8.1 or greater.

USB

USB Series-A and Series-B Plugs and Receptacles

USB Data Rates

FireWire

• A very fast external bus standard that supports data transfer rates of up to 400 Mbps (400 million bits per second).

• Products supporting the 1394 standard go under different names, depending on the company.

• Apple, which originally developed the technology, uses the trademarked name FireWire.

• Other companies use other names, such as i.link and Lynx, to describe their 1394 products.

FireWire• A single 1394 port can be used to connect up 63

external devices. • In addition to its high speed, 1394 also supports

isochronous data -- delivering data at a guaranteed rate.

• This makes it ideal for devices that need to transfer high levels of data in real-time, such as video devices.

• Although extremely fast and flexible, 1394 is also expensive.

• Like USB, 1394 supports both Plug-and-Play and hot plugging, and also provides power to peripheral devices.

Firewire, IEEE 1394• IEEE 1394 is a standard interface for connecting

storage, digital video and many other devices to your computer.

• Developed by Apple computer and trademarked with the name Firewire, IEEE 1394 offers data bandwidth up to 40 megabytes/second.

• One IEEE 1394 port can support up to 63 devices, with the assistance of one or more IEEE 1394 hubs.

• The IEEE 1394 standard has special modes for transferring video and other "synchronous" information, making it ideal for communicating with video cameras.

• The version of IEEE 1394 developed by Sony for its video equipment is called i.LINK.

IEEE-1394 Cable, Socket, and Connector Plug

USB and IEEE-1394 Comparison

Daisy chaining allows

FireWire vs. USB

Keyboard/Mouse Interfaces

Keyboard/Mouse Connector Signals

Joystick Port

Sound Blaster Cards with different Connectors

InfraRed Data (IrDA) Connector on Motherboard