Touch motion detection method, circuit, and system

1. A touch controller, comprising:

a touch frame processing component adapted to receive sensor signals indicating a touch point on a touch screen, the touch frame processing component operable to process the sensor signals to generate touch information associated with each touch point, the touch information including a location of the touch point and one of a touch-in, touch-out, and touch-motion type of event associated with the touch point;

a touch coordinate processing component coupled to the touch frame processing component, the touch coordinate processing component operable to

receive the touch information from the touch frame processing component; and

determine whether to report the touch information for touch-motion events associated with a current touch point by

determining a difference between the location of the current touch point and the location of a previously detected touch point,

assigning to each touch-motion event a motion status that includes either a stationary state or an in-motion state,

reporting the touch information associated with the current touch point when the difference is greater than a motion tolerance threshold, and

selectively outputting a touch information signal based on the corresponding motion status when the difference is less than the motion tolerance threshold,

and

a FIFO buffer circuit that stores touch information and provides the touch information to applications external to the touch controller on a first-in-first-out basis upon detection of a touch-out event or a touch-in event and in the absence of a touch-motion event.

2. The touch controller of claim 1 , wherein the touch coordinate processing component is operable to always report a touch-in type of event.

3. The touch controller of claim 1 , wherein the touch coordinate processing component is operable to always report a touch-out type of event.

4. The touch controller of claim 1 , wherein each component comprises a software module executing on suitable digital circuitry.

5. The touch controller of claim 1 , wherein the touch information further includes pressure and size information for each touch point.

6. A method of determining whether to report the detection of a touch-motion event in an electronic device including a touch screen, the method comprising:

determining a difference between the location of a first touch point and the location of a subsequently detected second touch point, irrespective of touch pressure;

reporting the touch-motion event when the difference is greater than or equal to a motion tolerance threshold,

determining whether or not the status is a stationary state when the difference is less than the motion tolerance threshold; and

reporting the touch-motion event when t-h-ea frame hysteresis value has not reached the threshold value, irrespective of touch pressure.

7. The method of claim 6 , wherein the first touch point is a reference touch point corresponding to the location of a previous touch event.

8. The method of claim 7 ,

wherein the reference touch point is the location of a prior touch event when the prior touch event is a touch-in event; and

wherein the reference touch point is the location of a prior touch event when the prior touch event is a touch-motion event and the difference is less than the motion tolerance threshold.

9. The method of claim 1 further comprising when the difference is greater than or equal to a motion tolerance threshold:

resetting a frame count; and

setting a location of a reference touch point equal to the location of the second touch point.

10. The method of claim 1 , wherein blocking reporting of the second touch event when the status is the in-motion state and a frame hysteresis value has reached a threshold value includes resetting the frame count.

11. An electronic system, comprising:

processing circuitry;

a touch screen;

a touch controller coupled to the processing circuitry and the touch screen, the touch controller including a touch frame processing component adapted to receive sensor signals from the touch screen, the sensor signals containing information about a touch point on the touch screen, the touch frame processing component operable to process the sensor signals to generate touch information associated with each touch point, the touch information including a location of the touch point and the association of one of a touch-in, touch-out, and touch-motion type of event with the touch point; and

a touch coordinate processing component coupled to receive touch information from the touch frame processing component and operable to:

determine, for touch-motion events, whether to report touch information associated with a current touch point to the processing circuitry,

determine a difference between the location of the current touch point and the location of a previously detected touch point,

assign a motion status to each touch-motion event,

report the touch information associated with the current touch point when the difference is greater than a motion tolerance threshold,

when the difference is less than the motion tolerance, to selectively block or report the touch information as a function of the corresponding motion status; and

a FIFO buffer circuit that stores touch information and provides the touch information to applications external to the touch controller on a first-in-first-out basis upon detection of a touch-out event or a touch-in event and in the absence of a touch-motion event.

12. The electronic system of claim 11 , wherein the processing circuitry comprises cellular telephone processing circuitry.

13. The electronic system of claim 11 , wherein the touch screen comprises a capacitive touch screen.

14. The electronic system of claim 11 , wherein the touch coordinate processing component is operable to report a touch event when the touch event is a touch-in type of event.

15. The electronic system of claim 11 , wherein the touch coordinate processing component is operable to report a touch event when the touch is a touch-out type of event.

16. The electronic system of claim 11 , wherein each component comprises a software module executing on suitable digital circuitry.

17. The electronic system of claim 11 , wherein the touch information further includes identification, pressure and size information for each touch point.

18. The touch controller of claim 1 wherein the touch information signal blocks reporting of the touch information when the motion status is stationary.

19. The touch controller of claim 1 wherein the touch information signal reports the touch information when the motion status is in-motion.