Active stylus with a parallel communication channel
A method of one embodiment includes generating, by a stylus, a composite signal. The composite signal includes a first signal having a first frequency, the first signal being used by a touch-sensing device to determine a position of the stylus relative to the touch-sensing device, and a second signal having a second frequency. The second signal may include status information such as an amount of force exerted on the stylus, battery information, orientation information, information indicating whether the stylus is within a threshold distance of the touch-sensing device, information indicating a status of a button of the stylus, and/or information indicating input from a user of the stylus. Furthermore, the second frequency is higher than the first frequency. The stylus sends the composite signal to the touch-sensing device, and an electrode array of the touch-sensing device may receive the composite signal. The touch-sensing device may determine a position of the stylus by processing the composite signal and may also determine the status information by processing the composite signal.
1. A method comprising:
generating, by a stylus, a composite signal comprising:
a first signal having a first frequency; and
a second signal having a second frequency, the second signal comprising information indicating an amount of force exerted on a portion of the stylus;
receiving, by an electrode array of the touch-sensing device, the composite signal;
determining, by the touch-sensing device, a position of the stylus by processing the composite signal;
determining, by the touch-sensing device, the information indicating the amount of force exerted on the portion of the stylus by processing the composite signal;
processing, by a first receive channel of the touch-sensing device, the composite signal received by the electrode array of the touch-sensing device to determine the position of the stylus, the first receive channel being configured to analyze the composite signal as a function of the first frequency; and
processing, by a second receive channel of the touch-sensing device, the composite signal received by the electrode array of the touch-sensing device to determine the information indicating the amount of force exerted on the portion of the stylus, the second receive channel being configured to analyze the composite signal as a function of the second frequency, the first and second receive channels being distinct.
2. The method of claim 1 , wherein the second signal further comprises at least one of:
information indicating an orientation of the stylus;
information indicating a status of a battery;
information indicating whether a portion of the stylus is within a threshold distance of a portion of a touch-sensing device;
information indicating a status of a button of the stylus; and
information indicating input from a user of the stylus.
3. A method comprising:
generating, by a stylus, a composite signal comprising:
a first signal having a first frequency, the first signal being used by a touch-sensing device to determine a position of the stylus relative to the touch-sensing device; and
a second signal having a second frequency, the second signal comprising information indicating a status of the stylus;
sending, by the stylus, the composite signal to the touch-sensing device;
processing, by a first receive channel of the touch-sensing device, the composite signal received by an electrode array of the touch-sensing device to determine the position of the stylus, the first receive channel being configured to analyze the composite signal as a function of the first frequency; and
processing, by a second receive channel of the touch-sensing device, the composite signal received by the electrode array of the touch-sensing device to determine the information indicating the status of the stylus, the second receive channel being configured to analyze the composite signal as a function of the second frequency, the first and second receive channels being distinct;
wherein the second frequency is different from the first frequency; and
wherein the composite signal comprises the first signal and the second signal combined using frequency division multiplexing.
4. The method of claim 3 , wherein the information indicating the status of the stylus comprises at least one of:
information indicating an amount of force exerted on a portion of the stylus;
information indication an orientation of the stylus;
information indicating a status of a button of the stylus;
information indicating input from a user of the stylus;
information indicating a status of a battery; and
information indicating whether a portion of the stylus is within a threshold distance of a portion of the touch-sensing device.
5. The method of claim 3 , wherein the second frequency is at least twice the first frequency.
6. The method of claim 3 , wherein generating the composite signal comprises:
generating, by the stylus, the first signal;
generating, by the stylus, the second signal; and
combining, by the stylus, the first signal and the second signal into the composite signal.
7. The method of claim 6 , wherein generating the second signal comprises modulating a carrier signal with a modulation signal comprising the information indicating the status of the stylus.
8. The method of claim 3 , wherein determining the information indicating the status of the stylus comprises analyzing the composite signal as a function of the second frequency.
9. A method comprising:
receiving, by an electrode array of a touch-sensing device, a composite signal comprising:
a first signal having a first frequency; and
a second signal having a second frequency, the second signal comprising information indicating a status of a stylus, the composite signal comprising the first signal and the second signal combined using frequency division multiplexing;
determining, by the touch-sensing device, a position of the stylus by analyzing the composite signal;
determining, by the touch-sensing device, the information indicating the status of the stylus by analyzing the composite signal;
processing, by a first receive channel of the touch-sensing device, the composite signal received by the electrode array of the touch-sensing device to determine the position of the stylus, the first receive channel being configured to analyze the composite signal as a function of the first frequency; and
processing, by a second receive channel of the touch-sensing device, the composite signal received by the electrode array of the touch-sensing device to determine the information indicating the status of the stylus, the second receive channel being configured to analyze the composite signal as a function of the second frequency, the first and second receive channels being distinct.
10. The method of claim 9 , wherein the information indicating the status of the stylus comprises at least one of:
information indicating an amount of force exerted on a portion of the stylus;
information indication an orientation of the stylus;
information indicating a status of a battery; and
information indicating whether a portion of the stylus is within a threshold distance of a portion of the touch-sensing device.
11. The method of claim 9 , wherein the second frequency is at least twice the first frequency.
12. The method of claim 9 , wherein determining the position of the stylus comprises analyzing the composite signal as a function of the first frequency.
13. A system comprising:
a stylus comprising:
a processor; and
a signal generator configured to generate a composite signal, the composite signal comprising:
a first signal having a first frequency; and
a second signal having a second frequency, the second signal comprising information indicating a status of the stylus, the composite signal comprising the first signal and the second signal combined using frequency division multiplexing; and
a touch-sensing device comprising:
an electrode array configured to receive the composite signal from the stylus;
a measurement circuit configured to process the composite signal;
a processor; and
a memory;
wherein the touch-sensing device is configured to determine a position of the stylus and the information indicating the status of the stylus by analyzing the composite signal;
wherein the measurement circuit of the touch-sensing device comprises:
a first receive channel configured to process the composite signal received by the electrode array of the touch-sensing device to determine the position of the stylus,
the first receive channel being configured to analyze the composite signal as a function of the first frequency; and
a second receive channel configured to process the composite signal received by the electrode array of the touch-sensing device to determine the information indicating the status of the stylus, the second receive channel being configured to analyze the composite signal as a function of the second frequency, the first and second receive channels being distinct.
14. The system of claim 13 , wherein the information indicating the status of the stylus comprises at least one of:
information indicating an amount of force exerted on a portion of the stylus;
information indication an orientation of the stylus;
information indicating a status of a button of the stylus;
information indicating a status of a battery; and
information indicating whether a portion of the stylus is a within a threshold distance of a portion of the touch-sensing device.
15. The system of claim 13 , wherein the second frequency is at least twice the first frequency.
16. The system of claim 13 , wherein generating the composite signal comprises:
generating, by the stylus, the first signal;
generating, by the stylus, the second signal; and
combining, by the stylus, the first signal and the second signal into the composite signal.
17. The system of claim 16 , wherein generating the second signal comprises modulating a carrier signal with a modulation signal comprising the stylus data.
18. The system of claim 13 , wherein determining the position of the stylus comprises analyzing the composite signal as a function of the first frequency, and wherein determining the information indicating the status of the stylus comprises analyzing the composite signal as a function of the second frequency.