Controller and method for controlling a capacitive touch screen or the like
First Claim
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1. A controller for a capacitive touch screen, comprising:
- a touch resolve subsystem that in response to a trigger input measures a plurality of capacitance values using a plurality of input pins; and
a processor that controls said touch resolve subsystem to acquire a baseline capacitance,to determine an interference map for each of a plurality of values of a parameter,wherein said interference map identifies an interference at each of said plurality of values of said parameter, and said values vary over an allowed range, and to select one of said plurality of values of said parameter based on said interference map in a calibration mode, and to acquire a frame comprising said plurality of capacitance values using said selected one of said plurality of values of said parameter in a normal operation mode,wherein said parameter comprises a number of scan pulses per scan line.
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Abstract
A controller for a capacitive touch screen includes a touch resolve subsystem and a processor. The touch resolve subsystem, in response to a trigger input, measures a plurality of capacitance values using a plurality of input pins. The processor controls the touch resolve subsystem to acquire a baseline capacitance in a calibration mode, to acquire a frame comprising the plurality of capacitance values in a normal operation mode, and to update the baseline capacitance to a new baseline capacitance in the normal operation mode in response to the frame without entering the calibration mode.
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Citations
9 Claims
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1. A controller for a capacitive touch screen, comprising:
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a touch resolve subsystem that in response to a trigger input measures a plurality of capacitance values using a plurality of input pins; and a processor that controls said touch resolve subsystem to acquire a baseline capacitance, to determine an interference map for each of a plurality of values of a parameter, wherein said interference map identifies an interference at each of said plurality of values of said parameter, and said values vary over an allowed range, and to select one of said plurality of values of said parameter based on said interference map in a calibration mode, and to acquire a frame comprising said plurality of capacitance values using said selected one of said plurality of values of said parameter in a normal operation mode, wherein said parameter comprises a number of scan pulses per scan line. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for acquiring information from a capacitive touch screen comprising:
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for each of a plurality of values of a parameter; performing a first scan of the capacitive touch screen using a value of a parameter, wherein said parameter comprises a number of scan pulses per scan line; performing a second scan of the capacitive touch screen using said value of said parameter; determining an interference at said value of said parameter based on a difference between said second scan and said first scan; and at said value of said parameter wherein said interference map identifies an interference at each of said plurality of values of said parameter, and said values vary over an allowed range, selecting a desired value of said parameter based on said interference map; scanning said capacitive touch screen using said desired value of said parameter; and determining a touch location in response to said scanning. - View Dependent Claims (9)
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Specification