Communication method for communication between pen and sensor controller

1. A communication method for communication performed between a pen and a sensor controller that, in operation, transmits uplink signals to the pen in a frame cycle, the communication method comprising:

acquiring, by the sensor controller, a timing at which pixels in a display are driven from a host processor;

determining, by the sensor controller, a frame cycle which is a fixed cycle according to a pixel driving cycle;

transmitting, by the sensor controller, a first uplink signal in a first frame, the first uplink signal including an identifier that indicates a type of data to be transmitted to the pen in a second frame, the second frame following the first frame; and

transmitting, by the sensor controller, a second uplink signal in the second frame, the second uplink signal including a value of data of the type indicated by the identifier included in the first uplink signal.

2. The communication method according to claim 1 , further comprising:

transmitting, by the pen, a downlink signal including response data as a response to the first uplink signal, the response data indicating that the data of the type indicated by the identifier is settable.

3. The communication method according to claim 2 , wherein the downlink signal includes a shortened pen-pressure value made up of a predetermined number of high-order bits of a pen-pressure value.

4. The communication method according to claim 3 , further comprising:

reporting, by the sensor controller, to the host processor the pen-pressure value restored from the shortened pen-pressure value included in the downlink signal that has been received.

5. The communication method according to claim 1 , further comprising:

determining, by the pen, whether or not the data of the type indicated by the identifier included in the first uplink signal is settable;

transmitting, by the pen, a first downlink signal including response data as a response to the first uplink signal when the pen determines, in the determining, that the data of the type indicated by the identifier is settable, the response data indicating that the data of the type indicated by the identifier is settable; and

transmitting, by the pen, a second downlink signal that does not include the response data, when the pen determines, in the determining, that the data of the type indicated by the identifier is not settable.

6. The communication method according to claim 5 ,

wherein the first downlink signal includes a shortened pen-pressure value made up of a predetermined number of high-order bits of a pen-pressure value, and

the second downlink signal includes the pen-pressure value.

7. The communication method according to claim 5 , wherein, when the sensor controller receives the second downlink signal as the response to the first uplink signal, the sensor controller does not transmit the second uplink signal.

8. The communication method according to claim 1 , further comprising:

transmitting, by the sensor controller, a third uplink signal in a frame before the first frame, the third uplink signal including a command for acquiring a version of the pen.

9. The communication method according to claim 8 , further comprising:

transmitting, by the pen, a downlink signal including information indicating the version of the pen as a response to the third uplink signal.

10. The communication method according to claim 9 , wherein when the version of the pen included in the downlink signal that has been received indicates that the data of the type indicated by the identifier is not settable to the pen, the sensor controller does not transmit the first uplink signal.

11. The communication method according to claim 1 , further comprising:

transmitting, by the sensor controller, a first uplink signal when the sensor controller detects that a pen which including an output device is in a contacting state, the first uplink signal including control information for controlling the output device; and

controlling, by the pen, the output device in response to reception of the first uplink signal.

12. The communication method according to claim 11 , further comprising:

detecting, by the sensor controller, that the pen is sliding on a touch surface,

wherein when the sensor controller detects that the pen is sliding on the touch surface, the sensor controller transmits the first uplink signal, and

when the sensor controller does not detect that the pen is sliding on the touch surface, the sensor controller does not transmit the first uplink signal.

13. The communication method according to claim 11 , wherein:

the sensor controller, in operation, transmits the first uplink signal to the pen in a frame cycle,

the communication method further includes:

acquiring, by the sensor controller, recognition information indicating a result of recognition of the pen, and

transmitting, by the sensor controller, a second uplink signal in a first frame, the second uplink signal including a latest value of the recognition information, and

the sensor controller transmits the first uplink signal in a second frame that is after the first frame.

14. The communication method according to claim 13 , wherein the recognition information includes a pen-pressure value of the pen, a movement speed of the pen, or an angle of the pen.

15. The communication method according to claim 13 , wherein the output device includes a haptic element, a light-emitting element, or an acoustic element.