Methods and apparatus to detect a touch pattern

1. A method comprising:

detecting a first portion of a touch sequence through operating in a first scan mode, wherein the detecting of the first portion includes detecting a first touch for a number of one or more scans of the first scan mode;

detecting a second portion of the touch sequence through operating in a second scan mode, wherein the detecting of the second portion includes detecting the first touch for a number of one or more scans of the second scan mode; and

recognizing the touch sequence based on the total number of scans of the first scan mode plus the total number of scans of the second scan mode being within a selected range.

2. The method of claim 1 , wherein the operating in the second scan mode includes operating in the second scan mode responsive to the detecting of the first portion of the touch sequence.

3. The method of claim 1 , wherein the operating in the first scan mode includes scanning at a first frequency and the operating in the second scan mode includes scanning at a second frequency that is greater than the first frequency.

4. The method of claim 1 , wherein the detecting of the first portion of the touch sequence includes scanning a targeted area of a touchscreen and the detecting of the second portion of the touch sequence includes scanning the targeted area.

5. The method of claim 1 , wherein the detecting of the first portion includes detecting one of a self-capacitance and a mutual capacitance indicating a start of the first touch and the detecting of the second portion includes detecting one of a self-capacitance and a mutual capacitance indicating a duration of the first touch and detecting a second touch.

6. The method of claim 5 , wherein the recognizing of the touch sequence includes determining a duration of the second touch and determining a duration between and end of the first touch and a start of the second touch.

7. The method of claim 1 , further comprising providing a wake up signal responsive to the recognizing of the touch sequence, the wake up signal to wake a processor.

8. The method of claim 1 , further comprising providing an access signal to a processor responsive to the recognizing of the touch sequence, the access signal to allow access to protected content.

9. An apparatus comprising:

a scan module configured to operate in a first scan mode and a second scan mode;

a presence module coupled to the scan module, the presence module configured to detect a first portion of a touch pattern through the first scan mode and detect a second portion of the touch pattern through the second scan mode, wherein the detection of the first portion includes detection of a first touch for a number of one or more scans of the first scan mode and the detection of the second portion includes detection of the first touch for a number of one or more scans of the second scan mode; and

a touch pattern module coupled to the presence module, the touch pattern module configured to recognize the touch pattern based on a sum of the number of one or more scans of the first scan mode and the number of one or more scans of the second scan mode being within a selected range.

10. The apparatus of claim 9 , comprising a mode selection module coupled to the scan module and the presence module, the mode selection module configured to signal the scan module to operate in the second scan mode responsive to the presence module detecting the first portion of the touch pattern.

11. The apparatus of claim 9 , wherein the scan module is configured to scan at a first frequency in the first scan mode and scan at a second frequency in second scan mode, wherein the second frequency is greater than the first frequency.

12. The apparatus of claim 9 , wherein the scan module is configured to scan a targeted area of a touchscreen when the scan module operates in the first scan mode and the scan module is configured to scan a targeted sub-area of the targeted area when the scan module operates in the second scan mode.

13. The apparatus of claim 9 , wherein the presence module is configured to detect, through the first scan mode of the scan module, a change in one of a self-capacitance and mutual-capacitance that indicates a start of the first touch detect, through the second scan mode of the scan module, a change in one of a self-capacitance and a mutual-capacitance that indicates a duration of the first touch, and detect a second touch.

14. The apparatus of claim 13 , wherein the touch pattern module is configured to recognize the touch pattern based on the duration of the first touch, a duration of the second touch, and a duration between an end of the first touch and a start of the second touch.

15. The apparatus of claim 9 , wherein responsive to the recognition of the touch pattern, the touch pattern module is configured to provide a wake-up signal to a processor to allow the processor to wake-up from a sleep mode.

16. The apparatus of claim 9 , wherein responsive to the recognition of the touch pattern, the touch pattern module is configured to provide an access signal to allow a processor to access protected content.

17. A system comprising:

a host processor;

a touch controller; and

a touch interface coupled with the touch controller, the touch controller comprising:

a scan module configured to scan at a first frequency and at a second frequency;

a presence module coupled to the scan module, the presence module configured to detect a first touch for a number of one or more scans at the first frequency, detect the first touch and a second touch for a number one or more scans at the second frequency, wherein the presence module is configured to scan at the second frequency responsive to the detection of the first attribute of the first touch; and

a touch pattern module coupled to the presence module, the touch pattern module configured to recognize a touch pattern based on the number of one or more scans at the first frequency and the number of one or more scans at the second frequency, and signal the host processor to wake up from a sleep mode responsive to the recognition of the touch pattern.

18. The system of claim 17 , wherein the scan module is configured to scan a targeted area of a touchscreen when the scan module scans at the first frequency and the second frequency.

19. The system of claim 17 , wherein the presence module is configured to detect a change in self-capacitance that indicates a start of the first touch and detect a change in self-capacitance that indicates the second touch.

20. The system of claim 17 , wherein the touch pattern module is configured to detect the touch pattern based on the duration of the first touch, a duration of the second touch, and a duration between the first touch and the second touch.