IEEE1394, USB 1.1 and video
Evgenie Rudometov, Victor Rudometov.
authors@rudometov.com
Article is grounded on substances of books "Arrangement of the multimedia computer" and "Motherboards and chip sets"
Cредства, providing hooking up to the computer of peripheral devices by means of consecutive buses, is provided with the extension of functionality, both computers, and arrangements. As the given arrangements modern videocameras can use, for example.
In the architecture of modern computers the increasing value is gained by the external buses which are for hooking up of various arrangements in which structure the appropriate controllers providing the necessary interface are provided. Today it can be, for example, hard disks, CD - DVD-arrangements, Iomega ZIP, transportable disk drive Hyundai ZIV, etc. Thus, perhaps, greatest interest is represented by digital cameras, and also videocameras Digital8 and MiniDV which prevalence steadily increases.
Practically all modern motherboards of standard ATX oriented to usage of processors of Pentium II, Celeron and Pentium III incorporate, at least, two ports USB, however any more are not a card rarity in which architecture it is provided four and even six ports USB.
Fig. 1. USB on the motherboard
Program support of interface USB is carried out by operating systems of Windows 95 OSR 2.1 and Windows 98 which are the most widespread systems. Besides, interface USB is supported also by such systems, as Windows NT and Windows 2000.
Now the given way is standard way of hooking up of peripheral devices to the computer. There are tens the arrangements, satisfying to this standard. Many corporations carry out sale and support of arrangements with interface USB.
The widespread variant of bus USB of the specification 1.1 (USB 1.1) possesses a data transfer high speed. Peak speed reaches 12 Mbit/with. This value considerably above similar metrics COM and LPT, accordingly in 100 and 20 times. But even such rather a high speed of data transfer which shows USB 1.1 insufficiently for many videounits which concern, for example, digital videocameras of standards Digital8 and MiniDV. More high-speed interface is necessary For similar arrangements.
The inventor of the new high-speed serial interface is Apple corporation. This corporation in 1986 has suggested to use a similar method at construction of the system bus, and also for hooking up of high-speed peripheral devices. Fire Wire, such name was given to it by Apple corporation, at first was developed as high-speed variant SCSI. After solution Apple to open the standard and cooperations with interested corporations in 1990 there was a description on this bus in the form of standard IEEE1394 (Institute of Electrical and Electronic Engineers 1394 — the standard of institute of engineers on the electrical engineer and electronics 1394). As well as USB, bus IeEe1394obespechivaet external hooking up of peripheral devices to the computer.
Transfer rate of bus IEEE 1394 — 100, 200, 400 Мбит/c, distance — to 4,5 m, quantity of arrangements — to 63. As well as USB, bus IEEE 1394 provides possibility of a reconfiguration of hardware of the computer without its turn off. According to accepted standard IEEE1394 exists two variants of plugs and cables.
The first variant with 6-contact IEEE1394 plug provides not only data transfer, but also power supplies feed on hooked up to the appropriate controller of the PC of arrangement IEEE1394. Thus the total current is limited by 1,5 value And.
The second variant with 4-contact IEEE1394 plug is calculated only for data transfer. In this case hooked up arrangements should have standalone power supplies.
Fig. 2. Plugs of cable IEEE1394
Fig. 3. Hooking up of arrangements to controller IEEE1394
Popularity of serial interfaces step-by-step grows. Thus if bus USB is oriented, basically, on input devices, the telecommunication equipment, printers, audio/video of the arrangement, IEEE 1394 — on high-speed arrangements, such as the storage device and digital video electronics.
Bus IEEE 1394 used for hooking up of various video and audio of the equipment (TVs, videorecorders, videocameras etc .), carrying out data transfer in a digital code, it is quite often known under i. LINK (trade mark Sony).
It is necessary to mark, that appropriate resources of the interface the video equipment builds in not only Sony corporation, but, as a rule, and other manufacturers of similar products.
The modern equipment of video abounds with functionally sated arrangements. Even more often the various resources providing convenience of operation, including customisation, indication and possibility to realise various video effects become mandatory attributes of such engineering. The elementary units of video-tape editing are quite often provided also.
However no built in resources can be compared to those possibilities which open before the user who has hooked up the videounits to the computer. And if with modern digital cameras, as a rule, there are no problems as today ports USB are standard attribute of motherboards digital videocameras demand controllers IEEE1394.
Unfortunately, while the arrangements supporting interface IEEE1394, as a rule, yet are not a part of mass computers. As a result users should solve the given problem independently. Thus it is necessary to pay attention at once to that fact, that manufacturers of videocameras persistently advocate appropriate resources of the development as which, as a rule, in any way it is impossible to name optimal neither at cost, nor on functionality. So, for example, experts of representation of Sony corporation in St.-Petersburg at purchase in 2000 of the digital camera urgently recommended some variants of controllers from easily soiled this corporation. Thus the minimum variant was estimated approximately in $500, and the price of high model even to recollect it would not be desirable. Possibly, there is no necessity to prove, that the similar position was followed and till now many sellers of shops of video of engineering adhere. And it when already couple of years it was possible to gain controller IEEE1394, practically, all for one hundred US dollars, the truth, in case of the arrangement of the minimum pattern back. Also it is possible to assert with confidence, that since then the prices for computer resources only decreased, and functionality grew. As the proof of the given statement it is necessary to result some examples of controllers IEEE1394.
Perhaps, the most simple and cheap arrangement is the package into which structure enter the controller, a cable and extremely short instruction on hooking up. The given package in an antistatic package into which all its components are packed is delivered.
Fig. 4. The controller with 3 ports IEEE1394
Fig. 5. The main chip of controller IEEE1394 with 3 ports
Advantage of the given package is the low price, which about time in ten below the specified price of package Sony. Nevertheless, for the spent money the user gains the arrangement with three plugs of ports IEEE1394, one of which is internal, and two — external.
Lack is absence in a software package without which, perhaps, it will be impossible to realise possibilities of the computer on performance, for example, video-tape editing and to imposing of various effects. Eventually, for the similar purposes hooking up of videounits to the computer also is carried out. Having gained the given package, the user should troubleshoot itself the software.
Therefore, possibly, bolshy interest represents the following package which structure except more perfect controller IEEE1394 includes also CD-ROM with the software.
Fig. 6. A package of the controller with 4 ports IEEE1394
Basis of the controller incorporating four plugs of ports IEEE1394, one of which is internal, and three — external.
Fig. 7. The main chip of controller IEEE1394 with 4 ports
It is necessary to mark, that for quite clear reasons this package is a little bit more expensive than the previous package, but also it gives much more possibilities.
Nevertheless, despite all advantages of the resulted package, undoubtedly it is considerable the big possibilities the package from Pinnacle Systems corporation possesses.
Fig. 8. A package from Pinnacle Systems corporation
Its structure and possibilities, also as well as some features resulted above packages, will be considered in following articles.
Packages have been given by the corporation the SCORPION ( www.scorpion.ru)
It is published in log "КомпьютерПрайс"