EE Times Under The Hood - October 8, 2007 - (Page 76) under the hood: COMPUTERS & GAMING modes and richer game play. Rather than just going bigger, the twopanel display provides distinct interfaces, each of which can take on different roles. To that end, while both LCD modules use essentially the same panel from Sharp (256 x 192, 18-bit color thin-film transistor), only the lower display has a touchscreen overlay. The Nintendo DS Lite provides two stereo speakers for virtual surround sound and an embedded microphone for games that require voice recognition. The unit also provides ports for both Nintendo DS and Game Boy Advance cartridges, along with terminals for the stereo headphone and microphone. Wireless communication is embedded within the DS Lite, based here on 802.11 with a Nintendo proprietary communications protocol. Specified range is 30 to 100 feet. Aside from allowing multiplayer games by wireless link, the modified Wi-Fi can also link up with the Nintendo Wii. Like the original Nintendo DS, the Lite allows users to select from English, Japanese, Spanish, French, German and Italian. 1,000-mA-hr battery Battery capacity has been bumped up in the Lite revision, from the 850milliampere-hour lithium-ion battery www.eetimes.com • www.techonline.com Analog content for both system power management and audio comes in an ASIC from Mitsumi Electric (MM3205B). The only remaining analog function outside of wireless is the touchscreen controller, which is based on AKM Semiconductor’s AK4181, supplanting Texas Instruments’ TSC20461 used in the original DS design. Simpler daughter card module The WLAN subsystem is a plug-in daughter card module that is a more-simplified version of the firstgeneration DS. Mitsumi again supplies the Wi-Fi connectivity with its MM3218, substituting a single-chip device for the separate baseband and transceiver chips of the original DS connectivity solution. The MM3218 appears visually at the die level to contain largely analog radio circuitry, suggesting that some of the baseband/MAC layer may be implemented back in the NTR B chip referenced earlier. Since the MM3218 is a custom part, there is no way to lean on a data sheet for guidance on this point. An oddly numbered STMicroelectronics memory chip suspected to be 256 kbytes of serial flash memory handles the MM3218’s local code-store needs. Using local memory suggests at least some of the Wi-Fi digital processing solution is resident on the Mitsumi chip. A daughter card implementation for Wi-Fi—while bucking the simplicity trend—has its advantages. As with the Apple TV teardown, the separation of function allows for independent FCC certification of the wireless bits, limiting early exposure of the DS Lite design as a whole and allowing the Wi-Fi to be upgraded on a path isolated from that of the rest of the DS Lite. The Lite update to the Nintendo DS is no surprise in view of the platform’s success. With 20 million of the original sold, cost reduction represents a good investment. In addition, cosmetic enhancements combine with component-count reductions in the DS Lite to improve consumer appeal and production costs. ■ IN BRIEF Nintendo has had a good run of late, with its Wii beating out Sony’s PS3 with higher sales. These days, perhaps consumers are finding that less is more, and the Nintendo DS Lite plies that theme with a new makeover of the company’s handheld game. With the DS Lite, the focus is more on cost reduction, improvements to industrial design and platform continuity, rather than the creation of a new technological tour de force. Component focus of the DS to a full 1,000-mA-hr capacity—enough juice to satisfy the claimed five to 19 hours of use time on a four-hour charge. Electronics for the Nintendo DS Lite center on a custom ARM-based CPU and graphics processor (CPU NTR B) containing both ARM-9 and ARM-7 cores. The former is presumed to do the media processing, while the latter handles control functions. The NTR B is supported by what is likely 4 Mbytes of NEC Electronics’ p-SRAM (μPD463 2512F1), though NEC lists only a μPD4632312A on its Web site, so some customization and ambiguity seem to be the case there. Given the success of the Nintendo DS platform, the updated DS Lite comes as no surprise. Despite a fairly condensed IC architecture, the DS Lite provides good opportunities in the interconnect and passive arena. Some 200 surface mount passives join the product’s seven chips, including some relatively high-value tantalum capacitors for filtering in the audio section and four SMT coils used for high-efficiency dc-dc conversion.Three timing devices—an Epson Toyocomm 32-KHz crystal for the real-time clock and two NDK oscillators for the CPU and WiFi clock—are found along with 13 connectors and sockets of various stripes. A simple but effective printed-circuit-board-based antenna from Mitsumi is also included, handling the DS Lite’s Wi-Fi connectivity; properly shaped PCB traces form the radiator/receptor with a planar unbalanced dipole topology.The “Lite” moniker notwithstanding, the Nintendo DS remains a solid consumer of components outside the IC realm. 76 Electronic Engineering Times, TechOnline | October 8, 2007 http://www.eetimes.com http://www.techonline.com
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