Rotatable knob interface

1. A sensing system comprising:

sensor electrodes;

a processing system coupled to the sensor electrodes and configured to:

operate, during a first period, a first subset of the sensor electrodes for input sensing by driving the first subset of the sensor electrodes with a sensing signal and receiving resulting signals from the first subset of the sensor electrodes;

drive, during the first period, a second subset of the sensor electrodes with a reference signal; and

drive, during the first period, a third subset of the sensor electrodes with a guard signal, wherein the second subset of the sensor electrodes is between the first subset of the sensor electrodes and the third subset of the sensor electrodes; and

a rotatable electronic device disposed over the sensor electrodes, the rotatable electronic device comprising:

a first coupling electrode;

a second coupling electrode configured to couple with and receive the reference signal from the second subset of the sensor electrodes; and

a conductive region configured to be rotated relative to the first coupling electrode and the second coupling electrode, wherein the resulting signals are affected based on a position of the conductive region relative to the first coupling electrode when the first coupling electrode is coupled with the first subset of the sensor electrodes.

2. The sensing system of claim 1 , wherein the processing system is further configured to:

drive, during a second period, the first subset of the sensor electrodes with the guard signal;

operate, during the second period, the second subset of the sensor electrodes for input sensing; and

drive, during the second period, the third subset of the sensor electrodes with the guard signal, wherein the first period and the second period are non-overlapping.

3. The sensing system of claim 2 , wherein the processing system is further configured to:

drive, during a third period, the first subset of the sensor electrodes with the guard signal;

drive, during the third period, the second subset of the sensor electrodes with the guard signal; and

operate, during the third period, the third subset of the sensor electrodes for input sensing, wherein the second period and the third period are non-overlapping.

4. The sensing system of claim 1 , wherein the processing system is further configured to:

drive, during the first period, a fourth subset of the sensor electrodes with the reference signal, wherein the fourth subset of the sensor electrodes is disposed between the first subset of the sensor electrodes and the third subset of the sensor electrodes.

5. The sensing system of claim 1 , wherein:

the first coupling electrode is aligned over and configured to couple with a first sensor electrode of the first subset of the sensor electrodes; and

the second coupling electrode is aligned over and configured to couple with a second sensor electrode of the second subset of the sensor electrodes.

6. The sensing system of claim 1 further comprising a display panel having the rotatable electronic device attached thereto.

7. The sensing system of claim 6 , wherein the processing system is further configured to update a display of the display panel during a display update period, and wherein the first period corresponds to a non-display update period during which the display of the display panel is not updated.

8. The sensing system of claim 1 , wherein the sensor electrodes are disposed in a matrix of rows and columns, and wherein the first subset of the sensor electrodes comprises a first two or more of the columns, the second subset of the sensor electrodes comprises a second two or more of the columns, and the third subset of the sensor electrodes comprises a third two or more of the columns.

9. A processing system comprising:

a sensor driver configured to:

operate, during a first period, a first subset of sensor electrodes for input sensing by driving the first subset of the sensor electrodes with a sensing signal and receiving resulting signals from the first subset of the sensor electrodes;

drive, during the first period, a second subset of the sensor electrodes with a reference signal; and

drive, during the first period, a third subset of the sensor electrodes with a guard signal, wherein the second subset of the sensor electrodes is between the first subset of the sensor electrodes and the third subset of the sensor electrodes;

wherein the resulting signals comprise effects corresponding to a position of a conductive region of a rotatable electronic device relative to a first coupling electrode and a second coupling electrode of the rotatable electronic device when the first coupling electrode is coupled with the first subset of sensor electrodes and the second coupling electrode is coupled with the second subset of the sensor electrodes.

10. The processing system of claim 9 , wherein the sensor driver is further configured to:

drive, during a second period, the first subset of the sensor electrodes with the guard signal;

operate, during the second period, the second subset of the sensor electrodes for input sensing; and

drive, during the second period, the third subset of the sensor electrodes with the guard signal, wherein the first period and the second period are non-overlapping.

11. The processing system of claim 10 , wherein the sensor driver is further configured to:

drive, during a third period, the first subset of the sensor electrodes with the guard signal;

drive, during the third period, the second subset of the sensor electrodes with the guard signal; and

operate, during the third period, the third subset of the sensor electrodes for input sensing, wherein the second period and the third period are non-overlapping.

12. The processing system of claim 9 , wherein the sensor driver is further configured to:

drive, during the first period, a fourth subset of the sensor electrodes with the reference signal, wherein the fourth subset of the sensor electrodes is disposed between the first subset of the sensor electrodes and the third subset of the sensor electrodes.

13. The processing system of claim 9 further comprising a display driver configured to update a display of a display panel, and wherein the rotatable electronic device is attached to the display panel.

14. The processing system of claim 13 , wherein the processing system is further configured to update the display panel during a display update period, and wherein the first period corresponds to a non-display update period during which the display panel is not updated.

15. The processing system of claim 9 , wherein the sensor electrodes are disposed in a matrix of rows and columns, and wherein the first subset of the sensor electrodes comprises a first two or more of the columns, the second subset of the sensor electrodes comprises a second two or more of the columns, and the third subset of the sensor electrodes comprises a third two or more of the columns.

16. A method for operating sensor electrodes, the method comprising:

operating, during a first period, a first subset of sensor electrodes for input sensing by driving the first subset of the sensor electrodes with a sensing signal and receiving resulting signals from the first subset of the sensor electrodes;

driving, during the first period, a second subset of the sensor electrodes with a reference signal; and

driving, during the first period, a third subset of the sensor electrodes with a guard signal, wherein the second subset of the sensor electrodes is between the first subset of the sensor electrodes and the third subset of the sensor electrodes,

wherein the first subset of the sensor electrodes is coupled with a first coupling electrode of a rotatable electronic device and the second subset of the sensor electrodes is coupled with a second coupling electrode of the rotatable electronic device, and wherein the resulting signals comprise effects corresponding to a position of a conductive region configured of the rotatable electronic device relative to the first coupling electrode and the second coupling electrode.

17. The method of claim 16 further comprising:

driving, during a second period, the first subset of the sensor electrodes with the guard signal;

operating, during the second period, the second subset of the sensor electrodes for input sensing; and

driving, during the second period, the third subset of the sensor electrodes with the guard signal, wherein the first period and the second period are non-overlapping.

18. The method of claim 17 further comprising:

driving, during a third period, the first subset of the sensor electrodes with the guard signal;

driving, during the third period, the second subset of the sensor electrodes with the guard signal; and

operating, during the third period, the third subset of the sensor electrodes for input sensing, wherein the second period and the third period are non-overlapping.

19. The method of claim 18 comprising updating a display of a display panel during a display update period, wherein the first period corresponds to a non-display update period during which the display panel is not updated, and wherein the rotatable electronic device is attached to the display panel.

20. The method of claim 16 , wherein the sensor electrodes are disposed in a matrix of rows and columns, and wherein the first subset of the sensor electrodes comprises a first two or more of the columns, the second subset of the sensor electrodes comprises a second two or more of the columns, and the third subset of the sensor electrodes comprises a third two or more of the columns.