 |
|
|
 |
||
 |
|
|
Compact Disk Player Front End Chipset Includes CD Text and 'Shockproof ' Memory Functions |
|
|
|
|
|
||||||||||||||||
St. Genis, France -- May 18, 1998 -- STMicroelectronics' TDA7521 CD Analog Front End and TDA7522 Servo Controller and Data Decoder integrated circuits together perform all of the front end functions of a car stereo compact disk player, controlling the actuators and processing the pickup head signal to generate analog and digital outputs. In addition the chipset includes a decoder for the new CD Text technology, which allows information like artists names, track listings, credits and even synchronized lyrics to be coded on an audio CD. Designed for car radio applications, the TDA7521+TDA7522 chipset has specific features, including an on-chip controller for 16Mbit external memory that allows up to nine seconds of audio to be temporarily stored, so that sound output can continue undisturbed even when a mechanical shock has momentarily disturbed head tracking. Other vehicle specific features include a wide -35 to +85°C operating temperature range and 4x speed capability for CD-ROM-based maps in car navigation systems. The TDA7521 Analog Front End is produced using 0.8 micron mixed bipolar-CMOS technology and integrates interface functions such as digital-to-analog converters, the pickup interface and actuator servo converters. A high end digital-to-analog converter with eight times over-sampling provides the direct audio output from this chip; a digital output stream is also available from the TDA7522. The TDA7521 is compatible with the STV5805 CD/DVD Optical Sensor. Produced in 0.35 micron CMOS technology, the TDA7522 houses all of the digital functions of the CD front end subsystem, including an ST7 microprocessor core that supervises overall operation of the CD player, and a DSP that performs both audio filtering and servo loop control. Also included are a 24Kbyte program ROM, 4Kbyte CDText RAM, 24 bit I/O port, the "shockproof" memory controller and a flexible digital interface that meets several different standards, including I2C, Sony-Philips Data InterFace (SPDIF), CD-ROM and CD Text Graphical Interface. Servo control for the loops that manage head tracking and laser focus are all digital, and an all digital PLL in the pickup channel assures a very wide capture range. To reduce power consumption the chip set can be forced into a low power mode where all clocks are halted. For system developers a special version of the TDA7522 is available which stores the ST7 code in an external RAM which is loaded through the I2C bus on startup by a small ROM-resident bootstrap program. Note for editors: CD Text CD Text is an extension to the Compact Disk Digital Audio standard that allows CD producers to add visual information to a normal audio CD. This standard can accommodate text displays of up to 21 lines of 40 characters plus bitmap images for record company logos. The standard also provides for the future addition of other data types such as JPEG photo files. Initially CD Text will be used to display limited but useful information like the name of the artist and title of the track -- features very useful in car stereos where a multiple disk changer is used. Later its use will extend to menu-based track selection and even synchronized lyrics. Radio listeners will benefit, too, because broadcasters can re-transmit the CD Text information through the existing RDS (RBDS in the USA) data channel for display on existing receivers. About STMicroelectronics STMicroelectronics is a global independent semiconductor company with strong European roots, whose shares are listed on the New York Stock Exchange (NYSE: STM) and on the Bourse de Paris. It designs, develops, manufactures and markets a broad range of semiconductor integrated circuits (ICs) and discrete devices used in a wide variety of microelectronics applications, including telecommunications systems, computer systems, consumer products and industrial automation and control systems. Further information on ST can be found at www.st.com. |
|
|||||||||||||||||
|
|
 |
|
|
|
|
||
