Sensing system with grasp detection

A rotatable interface, comprising:

• a first plurality of interface electrodes configured to signal rotation of the rotatable interface;
• a processing system configured to:
• drive, during a first sensing period, a first plurality of sensing electrodes of a set of sensing electrodes in a sensing region with first sensing signals;
• determine, from first resulting signals, a grasp of the rotatable interface;
• drive, during a second sensing period, a second plurality of sensing electrodes of the set of sensing electrodes in the sensing region with second sensing signals;
• and
• determine, from second resulting signals, rotation of the rotatable interface.

A method for a detecting user input to a rotatable interface, which at least partially overlaps a sensing region of a display, the method comprising:

• transmitting, during a first sensing period, first sensing signals to a first plurality of sensing electrodes of a set of sensing electrodes in the sensing region;
• receiving first resulting signals, wherein the first resulting signals correspond to the first sensing signals;
• determining, from the first resulting signals, a grasp of the rotatable interface;
• transmitting, during a second sensing period, second sensing signals to a second plurality of sensing electrodes of the set of sensing electrodes in the sensing region;
• receiving second resulting signals, wherein the second resulting signals correspond to the second sensing signals;
• and
• determining, from the second resulting signals, rotation of the rotatable interface.