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Pioneer MP3 player resembles Nano

Posted: 06 Mar 2007 ?? ?Print Version ?Bookmark and Share

Keywords:DSP? DAC? flash memory? Diamond? Apple?

Every once in a while we take a retro look at products to help calibrate the pace of change in CE. Particularly when there are modern parallels for the product category, a look at the past can be enlightening and (for me, anyway) a bit amusing. In tidying up the Portelligent "morgue," which has product teardowns dating back to the early 1990s, an old gem resurfaced: the Diamond Rio PMP300 MP3 player.

The PMP300 launched in 1998 as the first commercially significant flash-based MP3 player. With a 1998 price tag of $200, the PMP300 contained 32Mbytes of storage, enough to hold about 12 songs. Although this sounds trivial today, the PMP300 was to some extent going up against CD-based players that, by definition, played an album's worth of content. By likewise holding a disk's worth of music, the PMP300 matched its nearest competitor in capacity, albeit at a higher price point. For the extra bucks, however, music lovers received a much more portable form factor and the benefits of a rugged device with no moving parts vs. the optical-drive-based equivalents. The PMP300 was about the size of a pack of playing cards at 8.9-by-6.4-by-1.6cm, and resembled some of the two-way pagers of the day in size and weight?a likely design target given the latter's popularity in the late '90s.

Familiar interface
A single-line LCD provided the visual interface, displaying only the track number. None of the modern expectations of artist and title information, album cover art or timing information was shown, but it was enough to get the job done. Much as is the case today, the control interface consisted of a circular set of buttons for backward and forward track skipping along with start, stop, pause and the option for repeat play and random mode. (Sound familiar?)

The PMP300 provided four different equalizer settings, and both MP2 and MP3 audio formats could be played. Support for multiple bit rates and variable-bit-rate MP3 was also standard. A SmartMedia slot gave the PMP300 an expansion path to a maximum of 64Mbytes, with cards up to 32Mbytes possible at the upper limit. A single AA alkaline cell powered the device for about 10hrs of average playback time and the host PC's parallel port gave means for interface and song upload.

Diamond Rio PMP300

Launched in 1998, PMP300 was the first commercially significant flash-based MP3 player.
Click image to view teardown diagram

Along with breaking open a new consumer market, the PMP300 broke some new legal ground. In a courtroom scene that sounds like it could come from today's headlines, the Diamond Rio was the subject of a lawsuit filed by the Recording Industry Association of America, which claimed the player violated the 1992 Audio Home Recording Act. Diamond received a favorable ruling in October 1998, however, clearing the path for development of the MP3 player market.

Nano resemblance
So how was this pioneer product made? Surprisingly, the overall PMP300 architecture bears a resemblance to one of today's most popular flash-based players, the Apple Nano. Key elements of the PMP300 were built from the growing availability of affordable NAND flash memory devices, and here four Samsung packages with 8Mbytes each (part number KM29U64000T) supplied the 32Mbytes of total internal memory. As in some other modern players, a NAND memory interface was required, and here an Actel A40MX04, a 6,000-gate FPGA, created the gateway between NAND flash and the system controller, an NEC microPD78P064GC 8bit microcontroller.

A Micronas MAS3507 MP3 decoder (actually a design from Intermetall, which was purchased by Micronas) provides for the system DSP, translating the compressed MP3 stored-media format to a flat, expanded digital-music equivalent. From there a Micronas/Intermetall MAS3550 DAC created the final analog output for delivery to the headphone jack.

Power management is now and was then an important consideration. While far less complex than today's solutions, the PMP300 utilized a Maxim MAX1706 DC/DC converter as an efficient means to boost the 1.5V AA battery cell to the 3.3V used for system power.

Simpler packaging
Packaging was less sophisticated than what's found in modern portable electronics, here requiring two boards to fit the entire surface-mount--but still peripheral--leaded-component set. Memory and control devices along with the LCD interface resided on one board while audio processing and power conversion filled a second of equal size, with a stacked board-to-board connector between the two.

Turning to a comparison with the Apple 2Gbyte Nano, we still see standalone memory for media storage, moving from four separate chips totaling 32Mbytes in the PMP300 to a single stacked four-chip memory package housing nearly two orders of magnitude more in flash storage capacity.

The dedicated digital audio processing and separate MCU of the PMP300 have migrated in today's Nano to a single media processor in the form of a Samsung chip. It combines system control and sophisticated sound and image processing on a common chip. As in the PMP300, however, the audio codec and associated headphone amplifier remain a separate device in the Apple product, likely reflecting a continued emphasis on output audio quality over maximum integration.

Power conversion in the Nano has escalated from the single switched supply of the PMP300 to a complex power-management unit combined with two other power devices. Likewise, memory topology in the Nano has become more complex. While NAND is still used for song storage in both units, the Nano relies on additional NOR flash code memory and 32Mbytes of buffer/scratch pad SDRAM.

Generalized partitioning approach
In sum, the PMP300 seems to have set a generalized partitioning approach for today's flash-based player, and both designs rely on a mix of separate device functions over more-integrated but less-flexible alternatives. While media features, storage and other user-interface features have come a long way, one can see common design philosophies in both today's Nano and the market-launching PMP300 that is eight years its senior.

Despite (and because of) the advancing component set, the standalone MP3 player is still with us in modern forms popularized by Apple, among many others. Diamond and Rio may be distant memories, but the PMP300 got a ball rolling that continues to gather steam. In short, the Rio bootstrapped a music and media market that is still shifting, in both how content is played and how it is bought.

- David Carey
President, Portelligent

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