Channel scan logic

• US 8,471,837 B2
• Filed: 03/12/2010
• Issued: 06/25/2013
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Vu, Minh-Dieu Thi, Wilson, Thomas James, Krah, Christoph Horst
• Primary Examiner(s): NGUYEN, KIMNHUNG T
• Application Number:
  US12/723,437
• Publication Number:
  US 20100164898A1
• Time in Patent Office: 1,201 Days
• Field of Search: 345173-179, 345/204, 178 1801- 1804, 710/14, 713/2, 714/27
• US Class Current: 345/204
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• 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 3/044 by capacitive means
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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

Abstract

A device that can autonomously scan a sensor panel is disclosed. Autonomous scanning can be performed by implementing channel scan logic. In one embodiment, channel scan logic carries out many of the functions that a processor would normally undertake, including generating timing sequences and obtaining result data; comparing scan result data against a threshold value (e.g., in an auto-scan mode); generating row count; selecting one or more scanning frequency bands; power management control; and performing an auto-scan routine in a low power mode.

Claims

1. Channel scan logic for compensating for touch sensor panel delay during a scan of the touch sensor panel, comprising:

memory configured for storing a plurality of demodulation values, the demodulation values for generating demodulation signals to demodulate a sense signal received from the touch sensor panel;

a register configured for storing a plurality of delay values associated with a plurality of touch nodes in the touch sensor panel to compensate for touch sensor panel delay; and

logic configured for receiving the demodulation values from the memory, and delaying the demodulation values in accordance with a delay value received from the register;

wherein the delay value is selected from the register in accordance with the touch node associated with the sense signal being demodulated.

2. The channel scan logic of claim 1, further comprising a demodulator coupled for receiving the delayed demodulation values and the sense signal and generating a demodulated sense signal.

3. The channel scan logic of claim 2, further comprising a channel timing generator configured for generating a timing sequence for an analog-to-digital converter (ADC), the ADC for converting the demodulated sense signal to a digital value.

4. The channel scan logic of claim 3, the timing sequence including an ADC reset section, an ADC acquisition section, and an ADC write section.

5. The channel scan logic of claim 1, further comprising a computing system that incorporates the channel scan logic, the computing system comprising:

a touch sensor panel comprising a plurality of sensors;

a touch event subsystem operatively connected to the plurality of sensors; and

a panel processor operatively connected to the touch event subsystem.

6. The channel scan logic of claim 5, further comprising a mobile telephone that incorporates the computing system.

7. The channel scan logic of claim 5, further comprising a digital audio player that incorporates the computing system.

8. The channel scan logic of claim 5, further comprising a personal computing device that incorporates the computing system.

9. A method for compensating for touch sensor panel delay during a scan of the touch sensor panel, comprising:

storing and reading out a plurality of demodulation values, the demodulation values for generating demodulation signals to demodulate a sense signal received from the touch sensor panel;

storing a plurality of delay values associated with a plurality of touch nodes in the touch sensor panel to compensate for touch sensor panel delay; and

delaying the read out demodulation values in accordance with a delay value selected in accordance with the touch node associated with the sense signal being demodulated.

10. The method of claim 9, further comprising demodulating the sense signal using the delayed demodulation values to generate a demodulated sense signal.

11. The method of claim 10, further comprising generating a timing sequence for converting the demodulated sense signal to a digital value.

12. The method of claim 11, the timing sequence including an analog-to-digital conversion (ADC) reset section, an ADC acquisition section, and an ADC write section.