了解嵌入式控制器的省電選項(xiàng)，以提高系統(tǒng)的功率效率

　　所有大小的嵌入式控制器提供各種操作模式，以節(jié)省電力和/或節(jié)省電池的能量，同時(shí)系統(tǒng)運(yùn)行和當(dāng)它是空閑的。然而，可用模式的數(shù)量已經(jīng)從兩個(gè)或三個(gè)增加到多達(dá)六個(gè)?？刂破髟O(shè)計(jì)者繼續(xù)通過(guò)允許系統(tǒng)設(shè)計(jì)者選擇性地關(guān)閉微控制器的不同部分和調(diào)整時(shí)鐘速率來(lái)降低操作功率，以便在執(zhí)行非時(shí)間關(guān)鍵任務(wù)時(shí)減慢控制器的速度。

　　如今，這個(gè)行業(yè)在許多不同的市場(chǎng)上使用微控制器——消費(fèi)者、醫(yī)療、工業(yè)、安全、計(jì)算機(jī)等。許多這些系統(tǒng)是電池供電，因此功耗是一個(gè)關(guān)鍵的規(guī)格，設(shè)計(jì)師必須密切關(guān)注。即使系統(tǒng)是線運(yùn)行的，功耗也可以是一個(gè)重要的規(guī)范，因?yàn)樵S多系統(tǒng)都是密封的外殼，并且在運(yùn)行過(guò)程中產(chǎn)生的熱量必須保持在最低限度，以防止這種系統(tǒng)過(guò)熱。能源效率的運(yùn)作也使得有可能消除風(fēng)扇或其他方案旨在消除熱量。

　　Tricks of the trade

　　Since the early days of microcontrollers， chip designers most often implemented microcontrollers with static logic rather than dynamic logic so that simple clock gating could be used to stop all processor activity and reduce the power consumed by the controller to near zero （often just the leakage current）。 Static logic allows all the gates or memories to retain their state so that the functions can pick up where they left off when the clock is switched back on. However， dynamic logic requires that the logic elements continually get some activity， much like DRAMs get refreshed， in order to maintain their logic state. Unfortunately that means dynamic logic continually consumes some power even when the processor is idling.