DIGITAL HUBBUB

UNDER THE HOOD

This topic brings out the elements which makes up digital hubbub. Just like a personal computer it also got a hardware side and a software side.

HARDWARE
At the core of a home entertainment hub are
Central Processing Unit
Digital signal processing chips
Hard disk drive
Universal serial bus port
PCMCIA connector
Ethernet jack
All these components are shown in the figure ( page )

· Central processing unit :- As in a computer system , CPU is the master of the hub. It deals with the data transfer that takes between different peripherals and hub. It checks on the parallel operations taking place in hub. It enroutes data packages to different operating units. t receives signals regarding the function to be done from the control panel or from a remote control Functions are like recording a video or writing an MP3 in a CD or retrieving the stored data. Based on the received signal the central processing unit generate signals which control other peripherals to perform the concerned operation.

· Digital signal processing chips :- The analog signals from various peripherals like a tv set or a tape recorder is received by analog to digital convertors . These digitized data is accessed by digital signal processing chips via their serial ports. These data streams are compressed for storage .For displays these stop data is expanded by the same digital signal processing chips. This processor has parallel operating functional units and this help in real time processing of data .

· Hard Disk Drive :- The hard disk drive is under a direct control of CPU via disk controller. As in any device a hard disk drive is used to store the data .The compressed data from the digital signal processing chips is written onto the hard disk drive and for displays the same data is accessed via CPU. It will require a capacity of several giga bytes even more than a 20 GB because a good video require a giga byte for an hour and good audio needs about a megabyte a minute.

· Universal Serial Bus (USB) :- The USB is a synchronous protocol that supports isochronous and asynchronous data and messaging transfers. This universal serial bus port is used to communicate data with portable MP3 music players , digital cameras etc.

· Personal Computer Memory card International Association (PCMCIA) :- PCMCIA cards are credit card size adapters which fit into PCMCIA slots found in most handheld and laptop computers. In order to fit into these small size drives, PCMCIA cards must meet very strict physical requirements. It is used in transferring data with non volatile memory cards or other devices.

· Ethernet Jack :- Hub requires communication with other personal computers as in a local area network.. Ethernet jack is the hardware used for the above said interface.










a magnifying look on

· dsp processor
· usb
· pcmcia


A436 PARALLEL VIDEO DSP CHIP
Features
· Overview
o Highly optimized and efficient, general purpose, very high performance, 512b advanced imaging parallel DSP and 32b RISC processor (no MMU) in a single chip in a single instruction stream
o Performance of 50,000 RISC MIPS for motion estimation and 3 billion MACS with only 100 MHz CPU clock
o Achieves very high performance with moderate CPU clock rate and main-stream fabrication
o Fully C software-programmable, parallel image processor optimized for real-time image/video processing/compression and RTOS
o Much faster, more efficient and easier to understand, optimize and use than other fast DSPs
o Directly software programmable in C as universal compressor (encoder)/decompressor (decoder) for multi-format, standards-based or proprietary image/video compression / streaming / decompression
o Provides fully software programmable video compression in real-time
o Provides powerful, flexible, fully software programmable, autonomous "smart" cameras that "watch" images themselves so people don't have to, providing "scene content analysis"
o Enhanced version (fourth generation Ax36 core) of proven A236 Video DSP Chip
o Scaled-down and reduced pin-count versions can be built on demand to satisfy less demanding applications requiring even-lower price points
· Easy to program - use C not microcode!
o Full software development environment includes C compiler, assembler, linker, loader, simulator and debugger
o Develop code using our parallel-enhanced ANSI-standard C compiler with assembly language output
o Simple parallel programming model supports parallel operations on structures using embedded parallel data types
o Use C for what it was intended for -- to provide tight control of the code generated
o You are in control - no need to embed assembly language in C programs or rely on precompiled subroutine libraries
o Evaluation board and evaluation "smart" camera board integrated with software development environment
o Supports modular development, licensing and protection of code by third-parties
o Open architecture with simple pipeline so efficient code can be written easily
o Simple but powerful 32b instruction set provides quick interrupt response time
o Tools automatically pack two scalar instructions into one 32b word when no parallel processing is needed, further reducing program size
o Three internal DMA controllers automatically build circular, multi-frame image/video buffers with programmable sizes in memory, providing a standardized format for video capture, processing and display
o uCLinux RTOS with TCP/IP and UDP/IP for Internet connectivity, and file system and device drivers (video input/output, IDE, USB, ethernet, PCMCIA)
· Very high useful performance (figures @ 100 MHz CPU clock)
o 32, 8b x 16b, or 16b x 16b, multiply-adds per CPU clock with 32b accumulation (3.2B MACS)
o 32 histogram, table look-up or zero-detection operations per CPU clock
o 32 x 16b, or 64 x 8b, plus one 32b, ALU operations per CPU clock
o 32 x 32b bit-realignment and 32 x 16b storage operations per CPU clock
o 64-point motion-estimation / pattern matching operation per CPU clock (50,000 RISC MIPS)
o Eight 4-point matrix-vector multiplies or convolutions per CPU clock (3.2B MACS)
o Four pairs of convolutions per CPU clock for implementing wavelets (3.2B MACS)
o 66 or 100 MHz CPU clock, and 100 or 133 MHz SDRAM clock
· Enhanced ports for imaging, multimedia and device control
o Three independent, asynchronously clocked, glueless, video-aware and packet capable, double-buffered parallel DMA ports, each data path is programmable as 8- or 16-bits wide, has video sync signals and supports live digitized video input or output, including all video buffering required, and also enable multiple A436's to work together for even higher performance
o Able to receive images from up to four image sensors, and produce a video output from them, simultaneously
o Able to provide high speed refresh to video output devices including video encoder chips, and field sequential color LCD microdisplays
o Bit-Programmable I/O port has 8 bit-programmable I/O pins for interface to switches, actuators, keypad and other devices; interrupts are fully programmable

o Buffered, full-duplex, Stereo Audio DMA Port provides handles 4-, 8- and 16-bit samples in little-endian and big-endian formats
o Buffered, full-duplex, programmable 2-wire/3-wire, Serial DMA Port controls/accesses external low speed and high speed devices including image sensors, video encoders and decoders, serial EEPROMs and flash memory cards
o Supports two video encoder/decoder chips and two audio CODECs simultaneously
o Two UART ports are fully programmable
o Two programmable interrupt timers
o Real time clock and CPU clock counter
o Internal debug device provides a built-in logic analyzer with trace capability for program debugging
o 32 MB address space; memory configuration is dynamically specified at boot-up
o Memory interface provides clock to SDRAM
o 5v-tolerant I/O and 3.3v SDRAM interface
USB BUS
The motivation behind the selection of USB for the Macintosh architecture is simple.
USB is a low-cost, high-speed peripheral expansion architecture that provides data transfer rates up to 12 Mbps.
The USB is a synchronous protocol that supports isochronous and asynchronous data and messaging transfers.
USB provides considerably faster data throughput for devices than does the Apple Desktop Bus (ADB) and the Macintosh modem and printer ports. This makes USB an excellent replacement solution for not only the existing slower RS-422 serial channels in the Macintosh today, but also the Apple Desktop Bus, and in some cases slower speed SCSI devices.
In addition to the obvious performance advantages, USB devices are hot pluggable and as such provide a true plug and play experience for computer users. USB devices can be plugged into and unplugged from the USB anytime without having to restart the system. The appropriate USB device drivers are dynamically loaded and unloaded as necessary by the Macintosh USB system software components to support hot plugging.

Better Device Expansion Model
The USB specification includes support for up to 127 simultaneously available devices on a single computer system. (One device is taken by the root hub.) To connect and use USB devices, it isn't necessary to open up the system and add additional expansion cards. Device expansion is accomplished with the addition of external USB multiport hubs. Hubs can also imbedded in USB devices like keyboards and monitors which provides device expansion in much the same way that the Apple Desktop Bus (ADB) is extended for the addition of a mouse through the keyboard or monitor. However, the USB implementation won't have the device expansion or speed limitations that ADB does.

Compact Connectors and Cables
USB devices utilize a compact 4-pin connector rather than the larger 8- to 25-pin connectors typically found on RS-232 and RS-422 serial devices. This results in smaller cables with less bulk. The compact USB connector provides two pins for power and two for data I/O. Power on the cable relieves hardware manufacturers of low-power USB devices from having to develop both a peripheral device and an external power supply, thereby reducing the cost of USB peripheral devices for manufacturers and consumers.



PCMCIA
Founded in 1990, the Personal Computer Memory Card International Association (PCMCIA), of which Quatech is a member, developed a set of standards by which additional memory could be added to portable systems. It soon became apparent that this same interface could be used to add I/O devices and hard disk drives as well, thereby dramatically increasing functionality of laptop computers.
Physical Characteristics
The PCMCIA specification 2.0 release in 1991 added protocols for I/O devices and hard disks. The 2.1 release in 1993 refined these specifications, and is the standard around which PCMCIA cards are built today.
PCMCIA cards are credit card size adapters which fit into PCMCIA slots found in most handheld and laptop computers. In order to fit into these small size drives, PCMCIA cards must meet very strict physical requirements as shown in Figure 6 below. There are three types of PCMCIA cards, Type I generally used for memory cards such as FLASH and STATIC RAM; Type II used for I/O peripherals such as serial adapters, parallel adapters, and fax-modems (this is the type of card Quatech manufactures); and Type III which are used for rotating media such as hard disks. The only difference in the physical specification for these cards is thickness.
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SOFTWARE
As in a normal personal computer software checks on user interface , applications etc . Software of digital hubbub can be considered as a series of layers. In the innermost is an operating system that manages resources such as storage or CPU timing . The next layer is the middle ware that handles such house keeping details as displaying text and graphics on TV screens. The middleware interpret the input from different panel or remote control and it enables the CPU to generate signals according to the concerned function. It also deals with the communication with the cable that supplies the digital video and data strings . The outermost layer handles several applications .These applications includes recording controls program guides and onscreen signup for additional services and games and even web browsers. It provides a search engine that with only a few button pushes could find all movie musical starring, for instance Elvis Presley, or action dramas with Jackiechan, or new episodes of your favourite home improvement show.Software for digital hubbub is provided by mediabolic Inc (SAN FRANCISCO).

MIDDLE
WARE
INNER MOST LAYER
OUTER
LAYER
SOFTWARE

NEOLOGISM IN DIGITAL HUBBUB
As far as an electronic component market is considered the success of a product relies on the compactness and cheapness of the product. As any electronic device digital hubbub is also required to be compact and cheap. Compactness is brought about by implementing chips with multi-functions or in other way it can be said as compactness can be brought by merging 2 or 3 chips to do a single function. There fore several electronics firm are doing lot of research and development to bring about a much compact and cheap digital hubbub. A few affords to make the digital hubbub compact and cheap as illustrated below.
In April, Conexant Systems Inc. (Newport Beach, Calif., formerly Rockwell Semiconductor Systems) announced a chip that combines digital TV reception with a cable modem. It lets cable operators sell broadband interactive services in a low-cost package that includes 100-plus TV channels.
In another effort, Cirrus Logic Inc. (Austin, Texas) has among its chips a combined DVD and digital-video chipset that powers Samsung's PVR. And on the computercentric side, there's Linksys Group Inc. (Irvine, Calif.). Best known for its pocket routers (units that connect small home or office networks to the Internet), it has a new chip that combines routing circuitry with a cable modem and a wireless network access point. Such a chip could be built into a stand-alone digital hub or slotted into a PC acting as a home server.
Still, how do engineers cram what used to be thousands of dollars worth of video and computer equipment into an under-$500 box? By designing chips to do multiple duty, points out Anthony Simon, director of marketing for chip maker Conexant. For example, adding cable-modem functions to a video chip cuts between $20 and $40 from the cost of a set-top box.
And at PVR maker TiVo Inc. (Alviso, Calif.), product marketing director Ted Malone is proud of the subtle economies the company engineered into its custom disk-controller chip. The chip can read data streams from the disk surface in whatever order is most efficient for the head and then reassemble the information before handing it off to the video section.
Meanwhile, the price of hard-disk drives has put enormous volumes of storage within reach of even a run-of-the-mill set-top box. Currently, a 40-GB drive, which stores more than 50 hours of video, sells for about $80 retail and much less wholesale. Even a small fraction of that disk space can store dozens of hours of audio and thousands of digital photos
The evolving interface

A first step is an interface like TiVo’s where you peck out the name of the show on a virtual on- screen board: as you type each letter, an adjacent display of potential matching titles gets shorter until only a few choices remain. Once the right show is found,recording its eposides is a matter of pressing just a button or two.
Mox is simplifying matters further by mapping the letters most likely to be typed next to the numbers 1 through 9 on the remote’s keypad. Typing text on a numeric keypad will be familiar to the millions of people who send text messages by cellular phone.

Dream versus reality
Any build-up to a single home gateway that controls your television, air conditioning, and e-mail will not come overnight, according to Jakob Nielsen. People won't replace their VCR, DVD player, and home network all at once, he points out.
Thus far, barring a few exceptions such as "universal" remote controls and serial control inputs for some cable boxes, manufacturers still seem focused on locking consumers into a single supplier. Whether that philosophy can stand up to the ultimate purpose of a digital hub—connecting all the disparate entertainment devices a consumer may own and even replacing some of them—is probably the crucial question for the evolution of this new technology









REFERENCES

1. WWW.SPECTRUM.IEEE.ORG/DIGITAL HUBBUB
2. Www.oxfordmicrodevices.com/A436_summary.html
.FEATURES
3. IEEE SPECTRUM MAGAZINE JULY 2002