cap1293三通道电容式触摸传感器接近检测与信号保护

　　The CAP1293 is a multiple channel capacitive touch sensor controller. It contains three （3） individual capacitive touch sensor inputs with programmable sensitivity for use in touch sensor applications. Each sensor input is calibrated to compensate for system parasitic capacitance and automatically recalibrated to compensate for gradual environmental changes. In addition， the CAP1293 can be configured to detect proximity on one or more channels with an optional signal guard to reduce noise sensitivity and to isolate the proximity antenna from nearby conductive surfaces that would otherwise attenuate the e-field. The CAP1293 includes Multiple Pattern Touch recognition that allows the user to select a specific set of buttons to be touched simultaneously. If this pattern is detected， a status bit is set and an interrupt is generated. The CAP1293 has Active and Standby states， each with its own sensor input configuration controls. The Combo state allows a combination of sensor input controls to be used which enables one or more sensor inputs to operate as buttons while another sensor input is operating as a proximity detector. Power consumption in the Standby and Combo states is dependent on the number of sensor inputs enabled as well as averaging， sampling time， and cycle time. Deep Sleep is the lowest power state available， drawing 5µA （typical） of current. In this state， no sensor inputs are active， and communications will wake the device.