Sony's VRD-MC1 is a standalone DVD writer that accepts a host of still and video image input media and transfers the files directly to DVD disk; no PC is required. Architecturally, the product resembles a DVD recorder (DVD-R) and its associated optical drive, with added bridge electronics that expand the input options well beyond the composite- or component-video input typical of conventional DVD-R systems.
Input options for still imagery come from support of five memory card standards. An array of connector slots accepts the Memory Stick/Memory Stick Duo from Sony, Secure Digital, xD Picture Card and CompactFlash memory cards. An IEEE 1394 Firewire interface (called i.Link by Sony) is available for digital video input. Composite-video and S-Video jacks allow import of the more traditional analog output of VHS tape players, camcorders and the like.
Figure: Board-level look at the VRD-MC1 DVD writer.
(Click to Enlarge Image)
The VRD-MC1 is only slightly larger than the Sony-manufactured optical-drive mechanism contained within its three-piece molded-plastic case, and all input/ output for the product rings the edge of the 68-mm-thick design. To keep the case size small, Sony elected to have an ac/dc power brick external to the design. A 2-inch-diagonal LCD module supplied by Au Optronic of Taiwan is mounted in a sloped, recessed opening in the upper enclosure--ready to be used for review and selection of the content to be written or for review of previously written DVD content.
Magnum Semiconductor — a spin-off of Cirrus Logic — is behind the two central processor devices (the Cirrus-marked chips pictured were branded prior to the formal transition to Magnum). The MS2688 DVD encoder is tasked with rendering input data to the MPEG-2 audio/video format required for the DVD-writing step. The MS8301 DVD processor decoder handles the reverse stream of reading from DVD for playback to the LCD or export to viewing means outside the VRD-MC1. In addition, 16 Mbytes of SDRAM from Micron and 4 Mbytes of Macronix NOR flash (for code) are linked to the MS8301, while two 8-Mbyte Micron SDRAMs serve the memory needs of the MS2688 encoder.
The design allows the internal control of the DVD-R capability to be suspended with a direct USB-to-disk interface, giving users the option of allowing an external host PC to run the show and make use of the drive directly. A set of Texas Instruments bus transceivers and buffers is used to select between control and interface of the optical drive. In normal operation, the bus connecting the two primary Magnum Semiconductor devices responsible for encode/decode hosts the DVD drive, but when an external PC wants to move in, the Cypress CY7C68013A USB host controller can take over, linking the PC directly. Details are a bit fuzzy, but a second USB controller from NXP (formerly Philips) is also present, perhaps multiplexed to the USB connector to handle the direct USB interface to PictBridge-compatible printers.
With the core engine of the design covered, there is still much going on to handle a rich set of inputs to the VRD-MC1. On the memory card front, a highly targeted device from OnSpec — the 90C46D — supplies a media interface chip capable of handling all five supported memory card standards. The fact that such a chip even exists is testimony to the niche ASIC opportunities arising from the dizzying array of storage card formats that have made their way to market in the last five to 10 years. For every case of consumer complexity, it seems the nimble semiconductor industry is ready to find a new piece of business to soothe the pain.
Whether S-Video or composite input is used as the source for recording DVD copies of your favorite movies, these more conventional video signals must first be digitized. Here, an NXP SAA7115 and Cirrus CS5340 provide the analog-to-digital conversion for video and audio signals, respectively. The Firewire interface used for digital video input is handled largely by the MS2688, but a TI TSB41AB2 transceiver addresses the IEEE 1394 physical layer still required.
This direct-to-DVD appliance is an effort to address the complexity of the ecosystem of devices it serves. By eliminating the sometimes cumbersome PC in the media-gathering and DVD-writing process, and by accommodating the vast array of storage card formats, Sony is shooting for simplicity. The irony, of course, is just how much engineering complexity can go into serving the "simple" objective. n
Component Focus
Sony's VRD-MC1 direct-to-DVD writer tries to bypass the PC but it can't bypass the need for connectors to get multiple media format into the product. In particular, the need to read multiple memory card formats presents a problem of how to keep the connector count (and slots) to a minimum. A special 3-in-1 memory socket from (marked TD) supports Sony's Memory Stick, SD and xD card formats in a single surface-mount connector. A Foxconn IEEE1394 (FireWire) connector serves the need of direct-from-camcorder inputs.
Unbranded connectors complete the "ring of I/O" around the board perimeter for DVD interface, Compact Flash card, MemoryStick Duo, composite video, S-Video, USB and power input. The distributed control and processing of the design means multiple clocks to serve the various asynchronous processors, here served by four different crystals from TXC of Taiwan.
David Carey is president of Portelligent (www.teardown.com). The Austin, Texas, company produces teardown reports and related industry research on wireless, mobile and personal electronics.
