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Gemei Case Study

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Gemei's Powerful New Portable Media Player Is Driven by Blackfin® —

Dongguan Gemei Electronics Technology Co. Ltd. (Gemei) develops and manufactures portable electronics products, including earphones and MP3/MP4 portable media players (PMPs). The company prides itself on its qualified staff, strong products, and reliable services. In China, PMPs are one of the hottest consumer products in the country, with users preferring to listen to, view, and store music, videos, video games, and photos on them in lieu of other types of portable devices, such as portable CD or DVD players.

With such a hot market for PMPs, it should come as no surprise that Gemei considered its new flagship X720 PMP as one of the most important product announcements the company will make this year. While most PMP players routinely support audio and video playback, additional features are required in order to remain competitive in today's market, and the right amount of processing power to support them is a key enabler for differentiation. To that end, when Gemei was looking for a processor for its X720 PMP, it chose a Blackfin® ADSP-BF531 signal processor from Analog Devices, Inc. (ADI). Gemei says that with its 400 MHz of performance, the Blackfin ADSP-BF531 processor allowed the company to develop a PMP with more features than previously possible.

Not Just Music, but Games and Cameras Too!

Gemei product"Traditional" portable media players (both hard disk or flash memory-based) can store/play back files in several digital video, audio, and image media formats. Today, however, manufacturers are looking for new features to make their player stand out from the crowd. One new feature many PMP manufacturers have added, and Gemei's X720 is no exception, is emulation support for games.

Another feature the X720 includes is a 130M-pixel internal digital camera –both daylight and nighttime models –that display pictures on the PMP's three-inch (960 x 240 pixel) low-temperature poly-silicon (LTPS) screen in JPEG/BMP/GIF formats. Users of the X720 PMP can also present slideshows using GIF format.

The X720 PMP can even function as a video recorder. The X720 includes support for the Audio Video Interleave (AVI) movie format for video with 320 x 240 resolution at 30 frames-per-second (fps), currently the most common file format for storing audio/video data. The device also supports display of MTV video captions.

For audio, the X720 PMP supports the open-source free lossless audio codec (FLAC), allowing users to play back compressed music files without removing any data from the streaming audio source. The PMP includes a 10-band graphic equalizer to increase the clarity of the high, mid-range, and lows of MP3 files, plus seven sound effects. With a software upgrade, the X720 will also support sound effects from SRS Labs and BBE Sound. The device also features a built-in FM tuner and a voice recorder.

The X720 includes up to one GB of internal storage. Users can also read and write to secure digital (SD) cards and MultiMedia Cards (MMCs) using the X720's SD slot.

Why Blackfin?

Gemei chose the Blackfin ADSP-BF531 processor because it is a low cost, high-performance processor designed specifically to meet the computational demands and power constraints of today's embedded audio and video applications. For previous PMP products, Gemei used processors from Telechips. With the Blackfin ADSP-BF531 processor, however, Gemei was able to develop its product as a "pure software solution," enabling the new PMP to contain a plethora of new features such as gaming, the FLAC audio format, and special sound effects, to name only a few. The "pure software" approach is also making it very easy for Gemei to upgrade its PMP with new features.

One reason Gemei found the Blackfin ADSP-BF531 so powerful is because Blackfin processors provide both micro-controller (MCU) and signal processor functionality in a unified architecture. The processors combine a dual-MAC state-of-the-art signal-processing engine with the advantage of a clean, orthogonal RISC-like microprocessor instruction set, and single-instruction, multiple-data (SIMD) multimedia capabilities into a single-instruction set architecture. The Blackfin's unique combination of processing attributes eliminates the need for separate digital signal and control processors, which reduces bill of material costs (BOM) and greatly simplifies hardware and software design tasks. With 400 MHz of performance, Gemei felt that the Blackfin ADSP-BF531 processor had the right amount of price/performance and flexibility to develop a PMP with a full complement of rich multi-media functionality. With Blackfin, Gemei also knew it could bring the X720 PMP to market very quickly.

Power to Spare

Equally important to Gemei was the Blackfin ADSP-BF531 processor's power management capabilities. Blackfin processors are designed in a low power and low voltage design methodology and feature dynamic power management, which is the ability to vary both the voltage and frequency of operation to significantly lower overall power consumption. Varying the voltage and frequency can result in a substantial reduction in power consumption, compared with just varying the frequency of operation. This translates into longer battery life for portable appliances. Gemei's new product runs on a 1600mAh battery, supporting 25 hours of audio playtime and seven hours of video playtime. Blackfin's power management capabilities greatly contribute to the long battery life of Gemei's X720 PMP.

Industry Standard Interfaces

Gemei took advantage of the Blackfin ADSP-BF531 processor's industry-standard interfaces, which helped the company develop its solution cost-effectively and quickly, without the need for expensive external components. The Blackfin ADSP-BF531 processor's peripherals are connected to the core via several high bandwidth busses, which provide flexibility in system configuration as well as excellent overall system performance. The system peripherals include a UART port, an SPI port, two serial ports (SPORTS), four general-purpose timers (three with PWM capability), a real-time clock, a watchdog timer, and a parallel peripheral interface (PPI). Gemei used the Blackfin's SPORT for its audio codec and FM radio, the PPI for its LCD and video in, and the SPI for NOR flash.

The Blackfin ADSP-BF531 processor also contains high-speed serial and parallel ports for interfacing to a variety of audio, video, and modem codec functions; an interrupt controller for flexible management of interrupts from the on-chip peripherals or external sources, and power management control functions. All of the peripherals, except for the general-purpose I/O, real-time clock, and timers, are supported by a flexible DMA structure. There is also a separate memory DMA channel dedicated to data transfers between the processor's various memory spaces, including external SDRAM and asynchronous memory. Multiple on-chip busses running at up to 133 MHz provide enough bandwidth to keep the processor core running along with activity on all of the on-chip and external peripherals.

Gemei leveraged the Blackfin's external bus interface unit (EBIU) for SDRAM, NAND flash, a USB controller, and a SC card interface. Gemei is also using an ADI ADV7179 NTSC/PAL video encoder in its signal chain.

For tools, Gemei took advantage of ADI's VisualDSP++ development environment that lets programmers develop and debug an application. This environment includes an easy-to-use assembler (which is based on an algebraic syntax), an archiver (librian/library builder), a linker, a loader, a cycle-accurate instruction level simulator, a C/C++ compiler, and a C/C++ runtime library that includes DSP and mathematical functions.

Gemei's future plans include Blackfin for certain, as the company is planning a series of PMP products with even more functionality-which, after reviewing the X720's lengthy list of features, is hard to envision.

For more information about Gemei, please visit Gemei Electronics Technology Company.

"One reason Gemei found the Blackfin ADSP-BF531 so powerful is because Blackfin processors provide both micro-controller (MCU) and signal processor functionality in a unified architecture."