Synaptics Incorporated
Minimizing latency for resonant input object detection and classification

Abstract:

A method includes driving, by the master controller, transmitter electrodes with a first transmitter signal having a first sensing frequency while transmitting a first trigger signal to slave controllers, obtaining a location of an input object determined from first capacitive measurements determined by the slave controllers using the first trigger signal, and performing a resonant frequency scan. The performing the resonant frequency scan is by performing for each possible resonant frequency of resonant frequencies: driving, by the master controller, only a subset of the transmitter electrodes with a second transmitter signal having the possible resonant frequency while transmitting a second trigger signal to the slave controllers, wherein the subset corresponds to the location of the input object. The slave controllers demodulate a resulting signal according to the second trigger signal to obtain a second capacitive measurements for the possible resonant frequency.