Channel scan architecture for multiple stimulus multi-touch sensor panels

Abstract

A channel scan architecture for detecting touch events on a touch sensor panel is disclosed. The channel scan architecture can combine drive logic, sense channels and channel scan logic on a single monolithic chip. The channel scan logic can be configured to implement a sequence of scanning processes in a panel subsystem without intervention from a panel processor. The channel scan architecture can provide scan sequence control to enable the panel processor to control the sequence in which individual scans are implemented in the panel subsystem. Type of scans that can be implemented in the panel subsystem can include a spectral analysis scan, touch scan, phantom touch scan, ambient light level scan, proximity scan and temperature scan.

What is claimed is: 
     
         1 . A computing device comprising:
 a touch sensor panel including a plurality of touch sensors; and   circuitry configured to perform a plurality of different types of scans of the touch sensor panel in a sequence set by a processor, without further intervention from the processor, the plurality of different types of scans including a touch scan to generate touch sense data indicative of an object touching or in proximity to the touch sensor panel.   
     
     
         2 . The computing device of  claim 1 , wherein the circuitry comprises stimulation circuitry configured to stimulate the touch sensor panel and sense channels configured to sense the touch sensor panel. 
     
     
         3 . The computing device of  claim 1 , wherein the touch scan to generate touch sense data comprises a multi-stimulation touch scan to generate the touch sense data, wherein the multi-stimulation touch scan includes concurrently stimulating the touch sensor panel with multiple stimulation frequencies or multiple stimulation phases. 
     
     
         4 . The computing device of  claim 1 , the plurality of different types of scans further including a spectral analysis scan to generate frequency selection data indicative of a clean frequency for use in the touch scan. 
     
     
         5 . The computing device of  claim 4 , wherein the spectral analysis scan includes performing in-phase and quadrature demodulation of different frequencies at one or more sense channels coupled to the touch sensor panel. 
     
     
         6 . The computing device of  claim 1 , the plurality of different types of scans further including a no stimulation scan to generate calibration data indicative of a baseline noise level associated with one or more of the plurality of touch sensors of the touch sensor panel. 
     
     
         7 . The computing device of  claim 1 , the touch sensor panel further including one or more light sensors;
 wherein the plurality of different types of scans further includes an ambient light level scan of the one or more light sensors to generate light sense data indicative of an ambient light level at the touch sensor panel.   
     
     
         8 . The computing device of  claim 1 , the touch sensor panel further including one or more proximity sensors;
 wherein the plurality of different types of scans further includes a scan of the one or more proximity sensors to generate proximity sense data indicative of the object in proximity to the touch sensor panel.   
     
     
         9 . The computing device of  claim 1 , further including a temperature sensor;
 wherein the plurality of different types of scans further includes a scan of the temperature sensor to generate temperature data indicative of temperature-related drift.   
     
     
         10 . The computing device of  claim 1 , wherein the touch scan is last of the plurality of different types of scans in the sequence set by the processor. 
     
     
         11 . A method comprising:
 receiving a scanning sequence from a processor; and   performing, by circuitry independent from the processor, a plurality of different types of scans of a touch sensor panel according to the scanning sequence without further intervention from the processor, the plurality of different types of scans including a touch scan to generate touch sense data indicative of an object touching or in proximity to the touch sensor panel.   
     
     
         12 . The method of  claim 11 , wherein the touch scan to generate touch sense data comprises a multi-stimulation touch scan to generate the touch sense data, wherein the multi-stimulation touch scan includes concurrently stimulating the touch sensor panel with multiple stimulation frequencies or multiple stimulation phases. 
     
     
         13 . The method of  claim 11 , wherein the plurality of different types of scans further including a spectral analysis scan to generate frequency selection data indicative of a clean frequency for use in the touch scan. 
     
     
         14 . The method of  claim 13 , wherein the spectral analysis scan includes performing in-phase and quadrature demodulation of different frequencies at one or more sense channels coupled to the touch sensor panel. 
     
     
         15 . The method of  claim 11 , the plurality of different types of scans further including a no stimulation scan to generate calibration data indicative of a baseline noise level associated with one or more touch sensors of the touch sensor panel. 
     
     
         16 . The method of  claim 11 , the plurality of different types of scans further including an ambient light level scan of one or more light sensors to generate light sense data indicative of an ambient light level at the touch sensor panel. 
     
     
         17 . The method of  claim 11 , the plurality of different types of scans further including a scan of one or more proximity sensors to generate proximity sense data indicative of the object in proximity to the touch sensor panel. 
     
     
         18 . The method of  claim 11 , wherein the plurality of different types of scans further including a scan of a temperature sensor to generate temperature data indicative of temperature-related drift. 
     
     
         19 . The method of  claim 11 , wherein the touch scan is last of the plurality of different types of scans in the sequence from the processor. 
     
     
         20 . The method of  claim 11 , wherein the plurality of different types of scans comprises a spectral analysis scan, a proximity scan and a multi-stimulation touch scan, wherein the multi-stimulation touch scan is performed when results of the proximity scan indicate an object within a threshold distance of the touch sensor panel, wherein the multi-stimulation touch scan is performed at a frequency determined from results of the spectral analysis scan.