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The following page content corresponds to the products formerly marketed by NEC Electronics

Applications > System Applications > Automotive Electronics >

Compressed Audio Decoder

With recent price drops in memory storage technologies, USB flash memory devices have gained broad popularity in the PC market. In the market for portable music players, digital music players with compressed music capabilities have rapidly gained popularity in place of CD and MD players. The common keyword shared by these two devices is USB, the global standard interface technology. As the USB products popularize the market, drivers are clamoring for players that could be connected to the car audio systems and let them enjoy the music in the cars.

Close-up View of Products and Technology

New solution: Integration of USB functions as an add-on to existing systems

uPD63901 from NEC Electronics contains basic software for USB-controller (that drives the LSI developed by users) and MP3, Windows Media Audio (WMA), or AAC format decoders (see notes below). This means that when car audio manufacturers are designing an audio system, they only need to develop applications for command control, and thus greatly reducing the time required for software development.

Pioneer of Industry: One chip integration of USB functions necessary for car audio

uPD63901 is the first-ever system LSI that integrates a USB 2.0-compatible (Full Speed at 12 Mbps) host controller, a digital signal processor (DSP) for decoding audio data recorded in MP3, WMA, and ACC formats, and a CPU for USB control. This all-in-one chip integration helps to save the space in the design.

iPod playback via USB

The system is capable of playing iPod music data via USB.

Notes:
MP3: Audio compression technology based on the MPEG-1 video standards.
When an audio file of the same quality as a CD recording is compressed by this format, it can be reduced to between 1/10 and 1/12 the size.
Windows Media: The audio compression format developed by Microsoft (US).
Windows Media™ is a registered trademark or brand of the Microsoft Corporation in the US and other countries.
ACC: Stands for Advanced Audio Coding. ACC is an audio compression technology for MPEG-2/MPEG-4 that was standardized by the ISO working group. ACC provides a compression rate 1.4 times higher than that of MP3, with almost equal quality.

Broad Product Lineup

We offer a broad lineup of products to accommodate not only mass-storage class, but also DRM specifications by Apple's, Microsoft's and others. Since software can be written into uPD63901, the desired added value can be achieved through the software installed. Car audio manufacturers can select those products from our lineup that meet their requirements for added value.

Block Diagram

Main Product Specifications

Built-in components: USB host controller, MP3/MWA/AAC decoder, 1MB SRAM, 32KB SRAM for data retention, audio DAC
USB control PCU package: 144-pin, 0.5mm plastic LQFP chip
Operating temperature range: -40°C to +85°C
Power supply voltage: 3.3V ±5%
Clock (connection oscillator): 16.9344MHz and 48MHz

(USB unit)
USB 2.0 full-speed compliance (12Mbps: built-in USB 2.0 FS host controller)
Open HCI specification release 1.0a compliance
Bus bridge installation, USB host control via serial PCI transfer
PCI clock: pclk = 27.09504MHz (16.9344MHz × 16/10)
Serial clock: sclk = 8.4672MHz (16.9344MHz/2)
Mass storage class: bulk only Built-in US overcurrent state input (OCI terminal), USB power control output (PPON terminal) installations for VBUS

(DSP unit)
Built-in 32 KB RAM retention capacity
Built-in 1MB SRAM
DSP unit: 24-bit operation, 24-it output
MPEG1Audio Layer3, MPEG2Audio LSF Layer3, WMA, MPEG2AAC,
MPEG4AAC-compatible (48kHz/44.1kHz/32kHz/24kHz/22.05kHz/16kHz/12kHz/11.025kHz/8kHz)
Built-in 2-channel (ΔΣ-type) 1-bit D/A converter (24-bit equivalent) and post filter