Methods and devices for touchscreen eavesdropping prevention
Touchscreen controllers and associated electronic devices are described which prevent eavesdropping of touchscreen activity. In one aspect, the present disclosure describes a touchscreen controller that includes a touch input interface for connecting to a touch-sensitive overlay of a touchscreen display and a touch output interface. The touch output interface provides an output in dependence on touch input received via the touch input interface. The touchscreen controller further includes an orientation sensor control output interface for connecting to one or more orientation sensors and an embedded processor coupled with the touch input interface, the touch output interface and the orientation sensor control output interface. The embedded processor is configured to generate an interrupt output signal for output on the orientation sensor control output interface. The interrupt output signal is configured to deactivate the orientation sensor for at least a period of time when the touch-sensitive overlay is activated with touch input.
1. A touchscreen controller comprising:
a touch input interface for connecting to a touch-sensitive overlay of a touchscreen display;
a touch output interface, the touch output interface providing an output, to a main processor, in dependence on touch input received via the touch input interface;
an orientation sensor control output interface for connecting to one or more orientation sensors; and
an embedded processor coupled with the touch input interface, the touch output interface and the orientation sensor control output interface, the embedded processor configured to:
detect an activation of the touch-sensitive overlay;
in response to detecting an activation of the touch-sensitive overlay,
activate a timer and determine whether a first period of time has elapsed, the timer expiring following the first period of time; and
provide an interrupt output signal for output on the orientation sensor control output interface, the interrupt output signal being configured to deactivate the one or more orientation sensor sensors while the interrupt output signal is being provided by the embedded processor, the interrupt output signal being provided for the duration of the first period of time and the interrupt output signal ceases being provided upon expiration of the timer,
wherein the embedded processor is distinct from the main processor,
wherein the first period of time is a predetermined period of time.
2. The touchscreen controller of claim 1 , wherein the embedded processor is further configured to:
in response to detecting the activation of the touch-sensitive overlay,
provide an output signal to the touch output interface indicating that the touch-sensitive overlay is activated.
3. The touchscreen controller of claim 2 , wherein the embedded processor is configured to provide the interrupt output signal to the orientation sensor control output interface before providing the output signal to the touch output interface that indicates that the touch-sensitive overlay is activated.
4. The touchscreen controller of claim 1 , wherein the embedded processor is configured to, following the first period of time, cease providing the interrupt output signal to the orientation sensor control output interface.
5. The touchscreen controller of claim 4 , wherein the embedded processor is further configured to:
after ceasing providing the interrupt output signal, detecting a new activation of the touch-sensitive overlay, the new activation being characterized by a transition from a state where the touch-sensitive overlay is not activated to a state where the touch-sensitive overlay is activated; and
in response to detecting the new activation, providing the interrupt output signal to the orientation sensor control output interface.
6. The touchscreen controller of claim 1 , wherein the first period of time is in the range of 10 ms to 100 ms.
7. The touchscreen controller of claim 1 , wherein the first period of time is in the range of 40 ms to 60 ms.
8. The touchscreen controller of claim 1 , wherein the embedded processor is configured to generate the interrupt output signal in response to detecting a new activation of the touch-sensitive overlay, the new activation being characterized by a transition from a state where the touch-sensitive overlay is not activated to a state where the touch-sensitive overlay is activated.
9. The touchscreen controller of claim 1 , further comprising a housing which houses the embedded processor and wherein the orientation sensor control output interface comprises an electrical contact externally exposed through an opening in the housing.
10. An electronic device comprising:
a touch-screen display having a touch-sensitive overlay and a touchscreen controller coupled to the touch-sensitive overlay;
a main processor having an input connected to a touch output interface of the touchscreen controller; and
an orientation sensor having an orientation sensor output interface coupled to the main processor and an orientation sensor control input interface, the orientation sensor being configured to selectively enable the orientation sensor output interface in dependence on a signal received from the orientation sensor control input interface, the touchscreen controller comprising:
a touch input interface for connecting to the touch-sensitive overlay; a touch output interface, the touch output interface providing an output, to the main processor, in dependence on touch input received via the touch input interface;
an orientation sensor control output interface coupled to the orientation sensor control input interface of the orientation sensor; and
an embedded processor coupled with the touch input interface, the touch output interface and the orientation sensor control output interface, the embedded processor configured to:
detect an activation of the touch-sensitive overlay;
in response to detecting an activation of the touch-sensitive overlay,
activate a timer and determine whether a first period of time has elapsed, the timer expiring following the first period of time; and
provide an interrupt output signal for output on the orientation sensor control output interface, the interrupt output signal being configured to deactivate the orientation sensor while the interrupt output signal is being provided by the embedded processor, the interrupt output signal being provided for the duration of the first period of time and the interrupt output signal ceases being provided upon expiration of the timer,
wherein the embedded processor is distinct from the main processor,
wherein the first period of time is a predetermined period of time.
11. The electronic device of claim 10 , wherein the orientation sensor is a gyroscope.
12. The electronic device of claim 10 , wherein the orientation sensor is an accelerometer.
13. The electronic device of claim 10 , further comprising a second orientation sensor having an orientation sensor output interface connected to the main processor.
14. The electronic device of claim 13 , wherein the second orientation sensor further comprises an orientation sensor control input interface connected to the orientation sensor control output interface of the touchscreen controller.
15. The electronic device of claim 13 , wherein the second orientation sensor is not coupled with the orientation sensor control output interface of the touchscreen controller.
16. The electronic device of claim 10 , wherein the embedded processor is further configured to:
in response to detecting the activation of the touch-sensitive overlay,
provide an output signal to the touch output interface indicating that the touch-sensitive overlay is activated.
17. The electronic device of claim 16 , wherein the embedded processor is configured to provide the interrupt output signal to the orientation sensor control output interface before providing the output signal to the touch output interface that indicates that the touch-sensitive overlay is activated.
18. The electronic device of claim 10 , wherein the embedded processor is configured to, following the first period of time, cease providing the interrupt output signal to the orientation sensor control output interface.
19. The electronic device of claim 18 , wherein the embedded processor is further configured to:
after ceasing providing the interrupt output signal, detect a new activation of the touch-sensitive overlay, the new activation being characterized by a transition from a state where the touch-sensitive overlay is not activated to a state where the touch-sensitive overlay is activated; and
in response to detecting the new activation, providing the interrupt output signal to the orientation sensor control output interface.
20. The electronic device of claim 10 , wherein the first period of time is in the range of 10 ms to 100 ms.