New TI DSPs target set-top box market

Electronic News, Nov 11, 1996

Texas Instruments' Digital Compression Products group has introduced the first two digital signal processors (DSPs) in a planned series of devices specifically designed for digital set-top box applications.

The TMS320AV7100 and -AV7110 DSPs each integrate onto one chip the duties of three separate chips needed for digital set-top box applications. The three elements that previously took a chip each are the ARM7T 32-bit RISC processor, a 16-megabit (16M) SDRAM, and an MPEG-2 decoder. The DSPs also integrate a variety of features including: a traffic interface manager, MPEG-1 audio decoder and decryption and encoding modules.

The difference between the devices lies in the special functions included on-chip, TI said. The AV7100 features algorithms specifically designed for the digital satellite system (DSS) standard while the AV7110 is designed with algorithms for the digital video broadcast (DVB) standard. Both devices run at 81MHz while consuming 3.3 volts.

"This is unleashing OEM designers from a prison of designs they have been confined to in the past," said Randall S. Ostler, Texas Instruments' marketing manager for the Digital Compression Products group. "You cannot do this kind of integration onto a single chip anywhere else. Where before designers were confined to running multiple chips with multiple memories they now have the flexibility and power on a single chip with a single memory."

The integrated ARM7T 40.5MHz processor uses a dual instruction set while supporting 8-, 16- and 32-bit data types. The processor allocates 25-user MIPS for application software integration as well.

The MPEG-2 graphics decoder provides eight simultaneous hardware graphics windows, extensive graphics APIs and multiple window formats such as programmable 256 CLUT and digital video output.

According to Mr. Ostler, a key feature of the DSPs is the traffic interface manager which consolidates processing memory into a single 16M SDRAM that allows for transport and descrambling, audio/video decoding and buffering as well as on-screen display generation and storage.

"Simply integrating the core functions in the design does not solve the cost reduction problem," said. Mr. Ostler. "TI's development of the traffic interface manager was critical in achieving cost reduction by consolidating the memory requirement of each function integrated into the AV7000 into a single bank of memory. The flexibility to dynamically allocate the system resources to the various functions makes the AV7000 a very cost-effective solution."

Both the TMS32AV7100 and the TMS320AV7110 are priced below $45 in a 240-pin PQFP package in 100,000-unit quantities, TI said. The TMS320AV7100 will sample in December and is slated to ship 2Q97, Mr. Ostler said. The TMS320AV7110 will sample in February of next year and will be in volume production in 2Q97 as well. Mr. Ostler said future versions of the AV7000 series will include Dolby AC-3 digital audio playback functions.

The AV7000 is supported by a library of graphics tools including compilers, assemblers, linkers and simulators for application software for controlling the user interface.