05-04-2010, 10:30 PM
FIREWIRE.ppt (Size: 2.51 MB / Downloads: 421)
Contents
Introduction
History
Characteristics
Architecture
Implementation
-Types of data transfer
-Bus Arbitration protocols
Standards
Types of connectors
USB vs FireWire
Application and Development
Introduction
FireWire is Apple Computer's version of a standard, IEEE 1394, High Performance Serial Bus, for connecting devices to your personal computer.
It offers high-speed communications and isochronous real-time data services.
The 1394 bus is a versatile, high speed, and inexpensive way to connect a wide variety of consumer electronic devices
Allows peer- to-peer device communication
History
Before FireWire and USB appeared, external devices were typically connected to a computer using serial and parallel ports .
In fact FireWire was introduced as a successor to the SCSI.
In the mid nineties, the connectivity situation began to improve dramatically with the introduction of FireWire and, a few years later, USB.
Contd..
FireWire is Apple Inc.'s name for the IEEE 1394 High Speed Serial Bus. It was initiated by Apple and developed by the IEEE P1394 Working Group
As of 2007, IEEE 1394 is a composite of four documents: the original IEEE Std. 1394-1995, the IEEE Std. 1394a-2000 amendment, the IEEE Std. 1394b-2002 amendment, and the IEEE Std. 1394c-2006 amendment
Sony's implementation of the system, known as "i.LINK"
characteristics
FireWire has a number of important characteristics other than its speed that have made it popular.
For example:
1. You use thin cables to make connections easier.
2. You can daisy chain up to 63 devices so only a single port is needed on the computer. (63 devices might as well be an infinite number because you'll run out of money long before you accumulate this many devices.)
3. It supports plug and play so you just plug in a device and the system will automatically recognize it.
4. It supports hot plugging (adding and removing devices with the computer on).
5. It distributes power so low-consumption devices can operate without a separate power cord. There are two types of cables: one contains two power lines and two data lines, the other just two data lines. There are also two different connector types, one with four pins, the other with six pins.
6. A very high-speed rate of data transfer that will accommodate multimedia applications (100 and 200 megabits per second today; with much higher rates later)
IEEE 1394 Architecture
Architecture
The IEEE 1394 standard defines three layers, implemented in every device The Physical Layer (often abbreviated PHY), the Link Layer, and the Transaction Layer
Transaction Layer is used to connect the FireWire device to a parallel bus, like PCI. It incorporates the devices registers and memory.
It responsible for asynchronous data transfer.
The Link Layer takes the register information obtained from the Transaction Layer and forms the packets that are to be sent over the bus
Architecture contd..
It is also responsible for the cycle control of the isochronous mode.
The physical (PHY) layer is the lowest layer of the 1394 interface and provides the transmission and reception of data bits, arbitration and the electrical and mechanical interface.
Any node with more than one physical port will re-clock and repeat any data it receives on any particular port onto all its other ports, so that the port transceivers are effectively bus repeaters.
Implementation
Bus configuration is carried out in three phases - bus initialization and reset, tree identification and self identification
Bus initialization occurs whenever a new peripheral is added to the bus or reconfiguration is needed. A bus reset forces all nodes to clear all their bus topology information and tree identification is then started
Each node knows only whether itâ„¢s a leaf node or branch. After tree identification each node has assigned its ports as being connected to eitherchildren or parents.
Contd ¦
The root requests self-identification from each of its child nodes which in turn recursively ask their children for self-identification .
Self-identification includes information on the speed capabilities and port connection status of each node
After this self-identification phase has completed each node has been allocated a bus address and the bus topology has been broadcast to all nodes on the bus.
Types of data transfer
IEEE 1394 provides two types of data transfer:
- asynchronous and isochronous
- Asynchronous is for traditional load-and-store applications where data transfer can be initiated and an application interrupted as a given length of data arrives in a buffer.
- Isochronous data transfer ensures that data flows at a pre-set rate so that an application can handle it in a timed way.
- For multimedia applications, this kind of data transfer reduces the need for buffering and helps ensure a continuous presentation for the viewer
Asynchronous Arbitration
The asynchronous bus arbitration protocol uses the concept of a fairness interval
As each node wins arbitration and gains access to the bus it resets its arbitration enable flag and does not enter into arbitration again in that fairness interval
After all nodes have gained access to the bus, each nodeâ„¢s arbitration enable flag is set during the arbitration reset gap and the process starts again
Isochronous Arbitation
Isochronous data is transmitted using the concept of channels
Each node that wishes to send isochronous data is allocated a channel under a 6 bit channel number
Once all isochronous channels have sent data then the bus is ready for asynchronous arbitration .
Isochronous data is transferred under the control of a cycle master. The cycle master is given the highest priority access to the bus
It Broadcasting a cycle start packet
Contd..
If the cycle master finds the bus to be busy it waits till is free and sends a cycle start packet.
Encoded within the cycle start packet is the cycle time - a 32 bit timer maintained by each isochronous node.
Enables all nodes to remain synchronized and allows nodes to know how much jitter has occurred.
Standards
There are currently two standards:
- the original FireWire, now referred to as FireWire 400 or IEEE 1394, and FireWire 800 or IEEE 1394b.
- As the names imply, the maximum speed of FireWire 400 is 400 Mbits per second, whereas FireWire 800 tops out at 800 Mbits per second.
- FireWire 800 is backwards-compatible, and unlike USB the FireWire bus speed is not diminished when a slower FireWire 400 device shares a FireWire 800 bus.
- The maximum cable length is currently 4.5 meters or around 15 feet.
Types of connectors
6-pin firewire 400 9-pin firewire 800 connector connector
USB vs FireWire
sequential sequential random random
read write read write
Speed comparison
Developments
Available now :-
Camcorders, desktop camera, DVCR; PC add-in cards for the PC and Mac; chips and cables.
The future? ...
Higher speeds, longer distances - I-8Gpbs, 25m hops.
Bridging - to isolate local high speed traffic, long distance connections between clusters.
Applications
Aircraft: IEEE 1394b is used in military aircraft developed for use as the data bus on the F-22 Raptor, it is also used on the F-35 Lightning II.[20]
NASA's Space Shuttle also uses IEEE 1394b to monitor debris (foam, ice) which may hit the vehicle during launch.
Automobiles: IDB-1394 Customer Convenience Port (CCP) is the automotive version of the 1394 standard.
Digital Video (DV) is a standard protocol used by nearly all digital camcorders
4 pin end 6 pin end
Some Pictures
PCI FireWire Card
References
Don Anderson FireWire System Architecture-IEEE 1394
IEEE 1394 bus by Adrian Paskins
www.faculty.iu-bremen.com
www.pcmcia.org
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please read https://seminarproject.net/Thread-firewire-ieee and https://seminarproject.net/Thread-firewi...nar-report for getting more about FireWire