藍(lán)牙技術(shù)在嵌入式系統(tǒng)設(shè)計(jì)中的應(yīng)用

　　提起藍(lán)牙，非工程師首先想到的是無(wú)線耳機(jī)，它似乎從幾乎所有智能手機(jī)用戶的耳朵中萌芽。另一方面，嵌入式設(shè)計(jì)師看到一種低成本、互操作的、電池友好的技術(shù)，可以使他們的產(chǎn)品與越來(lái)越多的消費(fèi)者和工業(yè)設(shè)備交換數(shù)據(jù)文件和多媒體流（圖1）。在本文中，我們將探討成功集成該技術(shù)的一些設(shè)計(jì)問(wèn)題，以及新一代專門為嵌入式應(yīng)用設(shè)計(jì)的藍(lán)牙設(shè)備的體系結(jié)構(gòu)和功能集。

　　Figure 1： Bluetooth， and its cousin Bluetooth low-power， provide an efficient， near-universal conduit for data between embedded applications such as glucometers （top）， blood pressure meters， or other health care equipment （bottom） and a standard smartphone or tablet computer.

　　Different profiles

　　The original Bluetooth specification1 and all of its variants operate in the in the globally unlicensed Industrial， Scientific， and Medical （ISM） 2.4 GHz short-range band using frequency-hopping spread-spectrum transmission. Nearly all devices on the market today support the Bluetooth v1.2 specification and its 720 kbit/s data rate. Even many low-cost products also support the V2.0/V2.1 +EDR specifications， which feature improved security， simpler pairing between devices， and modes which enable reduced power consumption. The recently-introduced Bluetooth low energy specification2 features dramatically-reduced power consumption at the cost of reduced data rates and shorter effective range.