微控制器如何使智能，更持久和可靠的接口

　　從根本上說(shuō)，微控制器可以被描述為與日益復(fù)雜的外設(shè)緊密耦合的邏輯處理單元。通過(guò)將這個(gè)數(shù)字域耦合到現(xiàn)實(shí)世界，外設(shè)的功能和性能是微控制器功能中的一個(gè)定義參數(shù)。

　　最近，焦點(diǎn)可能轉(zhuǎn)向了MCU核心，但應(yīng)用程序仍然很大程度上定義了所需的外圍設(shè)備集。MCUs繼續(xù)降低處理成本，更加多樣化和專(zhuān)用外設(shè)的出現(xiàn)，增強(qiáng)通用I/O（GPIO）的專(zhuān)用接口。

　　在最簡(jiǎn)單的形式中，專(zhuān)用接口可能只是比較器，而不是ADC，但越來(lái)越多的外圍設(shè)備將激發(fā)（電壓或電流源）和測(cè)量（如ADC或DAC或電流感應(yīng)輸入）結(jié)合起來(lái)。GPIOs是否應(yīng)該由特定應(yīng)用程序接口取代現(xiàn)在是經(jīng)常的事大小的潛在市場(chǎng)和節(jié)約成本，可能會(huì)導(dǎo)致大量。一個(gè)這樣的應(yīng)用空間是觸摸傳感器接口。

　　低成本觸摸接口的需求正在增長(zhǎng)，因?yàn)樵黾咏换バ缘哪芰Σ粌H在一系列設(shè)備中提供更大的控制，而且也越來(lái)越受到人們的期望。

　　Touch technology

　　Historically， the most prevalent form of touch sensing has been resistive-based， where the sensing surface may overlay a screen or printed panel. The benefits of this approach are its simplicity and low cost; requiring few resources， it also has a relatively low-processing overhead， but may also be implemented using dedicated function blocks.

　　Typically， a resistive-screen interface operates by detecting small resistive changes across a planar surface formed by two conductive materials separated by an insulator. When pressure is applied to one surface， the resistance measured reduces. However， the key to this technology is in detecting where on the surface the pressure is applied in X and Y coordinates， which is ultimately dictated by the resolution. The smallest detectable location of an analog-resistive interface would typically be defined by the size of the surface， the absolute excursions of the resistance measurable， and the resolution of the ADC used to measure the resistance， and translate into a digital value.