AUTONOMOUS, ALWAYS ACTIVE, ENERGY-SAVING SAMPLE FOR CAPACITIVE MATRIX

摘要

Scanning systems and methods are disclosed that eliminate CPU interventions or interrupts when performing sensor scans of a touch interface, support a low-power sensing process without the need for periodic wake-up of the CPU, and are scalable for a multi-channel or multi-chip sensor configuration to support large touchscreens or a large number of sensors. A sensor scanning module can operate in a chained scan using direct memory access mode (CS-DMA mode) or autonomous scanning and multiple scanning (AS-MS) mode to scan all sensors within a frame without the need for a CPU Intervention is required or CPU interrupts are generated after each scan in the frame. The sensor scanning module can operate autonomously in an always-on, low power consumption scanning mode (LP-AOS) for multiple frames without CPU interaction until a touch event is detected. The CPU can work in an energy-saving idle state during the scan, which ensures a constant frame rate and a low latency period between touching the system and waking up.