Channel scan logic

• US 9,063,601 B2
• Filed: 07/31/2014
• Issued: 06/23/2015
• 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 H.
• Primary Examiner(s): NGUYEN, KIMNHUNG T
• Application Number:
  US14/448,893
• Publication Number:
  US 20140340345A1
• Time in Patent Office: 327 Days
• Field of Search: 345173-179, 345/204, 178 1801- 1804, 710/14, 713/2
• US Class Current: 1/1
• 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. A touch subsystem, comprising:

one or more sense channels configurable for receiving one or more sense signals from an event-sensitive panel and providing an output signal indicative of an event or no-event condition on the panel; and

channel scan logic coupled to the one or more sense channels and configured to control the one or more sense channels to autonomously scan the event-sensitive panel substantially free of intervention from a processor.

2. The touch subsystem of claim 1, further comprising:

driver logic configurable for providing one or more stimulation signals to the event-sensitive panel;

wherein the channel scan logic is coupled to the driver logic and configured to control the driver logic to selectively apply the one or more stimulation signals to drive lines of the event-sensitive panel.

3. The touch subsystem of claim 1, further comprising:

memory configured for storing a plurality of demodulation values, the demodulation values for generating demodulation signals to demodulate the one or more sense signals received from the event-sensitive panel.

4. The touch subsystem of claim 3, further comprising:

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

logic configured for receiving a demodulation value from the memory, and delaying the demodulation value 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.

5. The touch subsystem of claim 4, the one or more sense channels comprising one or more demodulators coupled for receiving the delayed demodulation values and the sense signal and generating a demodulated sense signal.

6. The touch subsystem of claim 5, the channel scan logic 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.

7. The touch subsystem of claim 6, the timing sequence including an ADC reset section, an ADC acquisition section, and an ADC write section.

8. The touch subsystem of claim 1, the channel scan logic comprising an address generator for generating a sensor address signal, the sensor address signal enabling at least some of a plurality of touch nodes on the event-sensitive panel to be scanned.

9. The touch subsystem of claim 1, the channel scan logic comprising delay logic configured to delay a demodulated waveform that is to be applied to a sense channel so that the demodulated waveform is applied to the sense channel at about the same time as a corresponding sense signal is received at the sense channel.

10. The touch subsystem of claim 1, the channel scan logic comprising delay logic configured to delay an analog to digital converter control signal to account for delay associated with a sense signal reaching a sense channel associated with the analog to digital converter.

11. The touch subsystem of claim 1, further comprising a computing system that incorporates the touch subsystem, the computing system comprising:

the event-sensitive panel; and

the processor.

12. The touch subsystem of claim 11, further comprising a mobile telephone that incorporates the computing system.

13. The touch subsystem of claim 11, further comprising a digital audio player that incorporates the computing system.

14. The touch subsystem of claim 11, further comprising a personal computing device that incorporates the computing system.

15. A method of scanning an event-sensitive panel, comprising:

receiving one or more sense signals from the event-sensitive panel at one or more sense channels and providing an output signal indicative of an event or no-event condition on the panel; and

controlling the one or more sense channels to autonomously scan the event-sensitive panel substantially free of intervention from a processor.

16. The method of claim 15, further comprising:

selectively applying one or more stimulation signals to the event-sensitive panel.

17. The method of claim 15, further comprising:

storing a plurality of demodulation values, the plurality of demodulation values for generating demodulation signals to demodulate the one or more sense signals received from the event-sensitive panel.

18. The method of claim 17, further comprising:

storing a plurality of delay values associated with a plurality of touch nodes in the event-sensitive panel to compensate for panel delay;

receiving a demodulation value; and

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

19. The method of claim 18, further comprising receiving the delayed demodulation values and the sense signal and generating a demodulated sense signal.

20. The method of claim 15, further comprising generating a sensor address signal for enabling at least some of a plurality of touch nodes on the event-sensitive panel to be scanned.

21. The method of claim 15, further comprising delaying a demodulated waveform that is to be applied to a sense channel so that the demodulated waveform is applied to the sense channel at about the same time as a corresponding sense signal is received at the sense channel.

22. The method of claim 15, further comprising delaying an analog to digital converter control signal to account for delay associated with a sense signal reaching a sense channel associated with the analog to digital converter.

23. A touch subsystem, comprising:

first means for receiving one or more sense signals from an event-sensitive panel and providing an output signal indicative of an event or no-event condition on the panel; and

second means for controlling the first means to autonomously scan the event-sensitive panel substantially free of intervention from a processor.

24. The touch subsystem of claim 23, further comprising:

third means for providing one or more stimulation signals to the event-sensitive panel;

wherein the second means further controls the third means to selectively apply the one or more stimulation signals to drive lines of the event-sensitive panel.

25. The touch subsystem of claim 23, further comprising:

means for storing a plurality of demodulation values, the demodulation values for generating demodulation signals to demodulate the one or more sense signals received from the event-sensitive panel.