Firmware methods and devices for a mutual capacitance touch sensing device

• US 8,334,849 B2
• Filed: 08/25/2009
• Issued: 12/18/2012
• Est. Priority Date: 08/25/2009
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Murphy, Thomas, Rathburn, Kevin, Leong, Keen Hun, Narasimhan, Sarangan
• Primary Examiner(s): Chow, Van
• Application Number:
  US12/547,408
• Publication Number:
  US 20110050618A1
• Time in Patent Office: 1,211 Days
• Field of Search: None
• US Class Current: 345/174
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

Disclosed are various embodiments of methods and devices for operating a processor or host controller in a mutual capacitance sensing device. Methods and devices for sorting motion reports provided to a host controller or other processor in a mutual capacitance sensing device, reporting touch points to a host controller or other processor in a mutual capacitance sensing device, improving noise robustness and navigation performance in a mutual capacitance sensing device, determining a touch area of a user'"'"'s finger on a touch panel or touchpad of a mutual capacitance sensing device, and avoiding false wakeups and minimizing power consumption in a mutual capacitance sensing device having a touch panel or touchpad are described.

Claims

1. A method of reporting touch points in a mutual capacitance sensing device, comprising:

(a) tracking individual touch points of a user on a touch panel or touchpad of the sensing device;

(b) reporting a plurality of individual touch points to registers of a processor;

(c) determining, in the processor, whether a particular touch point from among the reported plurality of individual touch points is a new touch point or an existing touch point;

(d) if the touch point is determined to be a new touch point, determining in the processor whether a touch force value associated with the new touch point is greater than a first threshold and then identifying the new touch point in the processor as a touch, and if the touch force value is less than the first threshold then identifying the touch point in the processor as a hover;

(e) if the touch point was previously detected as a hover, determining in the processor whether the touch force value associated with the touch point is greater than the first threshold and then identifying the touch point in the processor as a touch, and if the touch force value is less than the first threshold then identifying the touch point in the processor as a hover;

(f) if the touch point was previously detected as a touch, determining in the processor whether the touch force value associated with the touch point is greater than a second threshold and then identifying the touch point in the processor as a touch, and if the touch force value is less than the second threshold then identifying the touch point in the processor as a hover; and

(g) repeating steps (a) through (f) in the registers and processor until all the reported individual touch points have been identified as touches or hovers.

2. The method of claim 1, wherein the reported individual touch points are processed in the processor to identify swipes.

3. The method of claim 1, wherein the reported individual touch points are processed in the processor to identify flings.

4. The method of claim 1, wherein steps (a) through (g) are carried out by firmware embedded in the processor.

5. The method of claim 4, wherein the firmware comprises computer code loaded into on-chip ROM.

6. The method of claim 5, wherein the firmware further comprises patch code loaded into on-chip RAM by a host controller after power up.

7. The method of claim 5, wherein a firmware reset is performed after power up.

8. The method of claim 1, wherein the first and second thresholds are updated and adjusted by the processor in accordance with the touch force values associated with the identified touches and hovers.

9. The method of claim 1, wherein the plurality of individual touch points are reported to the processor by the registers.