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Audi Case Study

Audi logoAudi A5's In-Vehicle Audio Subsystems Being Driven by Blackfin® and SHARC® Processors —

The Audi A5 is classic sport-styled Coupé featuring sculptured bodywork and aerodynamic lines. The harmonious lines of the car's interior and its precise instrument panel, which is fully integrated into the dashboard, play well with the vehicle's athletic exterior. Thanks to Blackfin® processors and other components from Analog Devices, Inc. (ADI), the head unit radio subsystem, with its graphical Multi Media Interface (MMI) "dashboard" display, makes certain the car's inner harmony truly resonates with its classic exterior excellence.

Audi A5 carA Blackfin ADSP-BF539 processor powers the Multi Media Interface of the Audi A5's radios, which are aptly named the Audi Symphony and Concert Radios for the extensive assortment of CD-quality music they generate for drivers/passengers. Optional digital audio broadcast (DAB) features are powered by an ADSP-BF532 processor. A different ADSP-BF532 processor drives an MP3-compatible 6-way CD changer. And one more Blackfin ADSP-BF532 processor drives the A5's Audi Music Interface, which integrates portable media players, such as the Apple iPod, for convenient dashboard display and easy steering-wheel control. An optional Bang & Olufsen (B&O) surround sound amplifier, which delivers the utmost in audio quality, is based on an ADI SHARC® processor, the de facto standard for high-fidelity sound in both home and automotive entertainment systems.

Other processor architectures were considered, but Blackfin was ideal as it offered the performance, scalability, and connectivity to handle audio decoding, DAB processing, and MMI control within Audi's automotive infotainment system. It also offered the supporting infrastructure to enable fast, low-risk development. ADI's reputation as a leader in high-end audio systems also helped to influence the decision as did the company's extensive portfolio of industry-specific third-party Intellectual Property (IP).

Why Blackfin Processor?

Blackfin processors provide automotive developers with the performance and connectivity they need to design electronics applications, particularly applications that require field upgradeability. Software flexibility such as this is critical for automotive applications because media formats and communications standards are in a constant state of change. In addition, Blackfin is unmatched in the industry for enabling automotive applications because of its combination of signal- and control-processing and multimedia support.

The Blackfin family integrates a rich set of industry-leading system peripherals, making the processors the platform of choice for next-generation automotive applications, such as Audi's. Developers for the Audi project took advantage of all of the peripherals the Blackfin architecture had to offer.

Under the Dashboard

A 533 MHz Blackfin BF539 processor controls the Audi Symphony/Concert Radios' MMI via the processor's parallel peripheral interface (PPI) port. The MMI was developed with a state of the art software tool for designing graphical user interfaces. This tool enabled the designers to produce a prototype of the MMI user interface and to easily explore additional customization.

An optional digital audio broadcast (DAB) feature is powered by a separate Blackfin BF532 processor. Because the Audi Symphony/Concert Radio is designed as a software-defined radio (SDR), Audi can implement new radio protocols easily through software updates. Future upgrades would require only a software flash of new IP to the Blackfin's programmable hardware.

Another Blackfin BF532 processor was used in the CD player - a product used in other Audi vehicles, to handle MP3 decode/playback and audio processing. This Blackfin processor also connects to the Media-Oriented System Transport (MOST), a bus widely acknowledged as the network of choice for integrated automotive multimedia systems. The Blackfin BF532 runs the MOST network stacks and protocol, and connects via the Blackfin serial bus.

A Blackfin BF532 processor also powers the Audi Music Interface. At 400 MHz, the processor features the right price/performance for this application, and the fact that the processor can perform both control and signal processing means it is capable of handling both audio processing and external device management. The Audi Music Interface enables users to control stereo audio sources, including USB sticks and iPod devices (generation 4 onwards) through the audio system and multi-function steering wheel. The interface also replicates the iPod display on the audio screen, including track titles.

A SHARC 21362 processor was selected for its high-performance, rich audio feature set, and well-earned reputation in the audio market to serve as the foundation of a surround sound B&O amplifier. The SHARC processor executes filter algorithms that optimize the audio, adapting it to the acoustics of a car cabin. The B&O amplifier is an option for the Audi A5 Coupé.

Exceptional Support

Developers on all of the design teams for the Audi A5 project used ADI's VisualDSP++ integrated development and debugging environment (IDDE), which enables efficient management of projects from start to finish from within a single interface. Key features of VisualDSP++ include native C/C++ compilers, advanced graphical plotting tools, statistical profiling, and the VisualDSP++ Kernel (VDK), which allows code to be implemented in a structured easy-to-scale manner. The developers also used ADI's onsite technical support, leveraging the experience and background of ADI engineers to solve complex hardware and layout issues.

Audi markets its A5 Coupé as one of the most impressive pioneering designs to date, inside and out, and Blackfin can take some of the credit for this. The car offers rich features, enabling hands-free operation of the high-fidelity audio systems and the ability to upgrade them in the future. That's a good investment.

For more information, visit Audi's website.

"Audi markets its A5 Coupé as one of the most impressive pioneering designs to date, inside and out, and Blackfin can take some of the credit for this."