Data processing device connected with display device and control method of display device

3:

• The data processing device according to claim 1, wherein the data transfer controller
• sends a return instruction for operating the stopped circuit in the display device to the display device when the data transfer controller returns from the intermission state to the normal state,
• transfers the image data in the image buffer to the display device at a second transfer rate higher than a first transfer rate predetermined as a standard rate when the data transfer controller receives a return completion notification indicating resumption of operation of the stopped circuit in the display device from the display device after sending the return instruction,
• releases an extension frame buffer area defined as an extension portion of the image buffer and changes a transfer rate of the image data in the image buffer to the first transfer rate, when there occurs a frame period in which image data stored in the extension frame buffer area has already been read out and new display image data has not been written into the extension frame buffer area while the image data in the image buffer is transferred to the display device at the second transfer rate.

7:

• The data processing device according to claim 1, wherein the data transfer controller
• determines the intermission period based on refreshing-related information obtained from the display device, when the update detection section detects a non-update of the image data in the image buffer for the predetermined time,
• shifts to the intermission state if the intermission period is longer than a predetermined reference period,
• stops a first circuit defined as a circuit which has time required for resuming operation not longer than a predetermined time among circuits to be stopped in the display device in the intermission state and thereafter shifts to a short intermission state different from the intermission state without extending the memory area of the image buffer, if the intermission period is not longer than the predetermined reference period, and
• returns to the normal state and resumes operation of the first circuit in the display device, when the update detection section detects a data update in the image buffer while the data transfer controller is in the short intermission state.

8:

• The data processing device according to claim 1, wherein the data transfer controller includes:
• a first interface circuit configured to transfer image data in the image buffer to the display device, and
• a second interface circuit configured to send a return instruction for operating the stopped circuit in the display device to the display device and receive a return completion notification indicating resumption of operation of the stopped circuit in the display device from the display device, when the data transfer controller returns from the intermission state to the normal state,
• wherein the second interface circuit is provided as a serial interface having a slower data transfer rate than the first interface circuit.

12:

• A method for enabling a data processing device to control a display device which is connected data-exchangeably therewith and has an intermission driving mode, in which the display device drives a display section in such a manner that a refreshing period during which an image displayed in the display section is refreshed and a non-refreshing period during which an image displayed in the display section is not refreshed are alternated with each other, the method comprising:
• an update detection step of detecting an update of image data in an image buffer in a memory section within the data processing device, the memory section being capable of storing image data for a plurality of frames each representing an image to be displayed in the display section, the memory section having, as the image buffer, a memory area including at least one frame buffer area;
• an updated-data transfer step of transferring image data stored in the image buffer to the display device by a first-in first-out method upon detection of a data update in the image buffer;
• an intermission step of assuming an intermission state for an intermission period determined as the non-refreshing period at most, upon detection of a non-update of the image data in the image buffer for a predetermined time;
• a buffer extension step of extending the memory area of the image buffer upon shifting to the intermission state;
• a return instruction step of sending a return instruction for operating a stopped circuit in the display device to the display device, upon detection of a data update in the image buffer in the intermission state;
• and
• a return-to-normal-state step of returning to a normal state, in which the image data is transferred to the display device in response to a data update detected in the update detection step, upon detection of a data update in the image buffer in the intermission state.

14:

• A non-transitory computer-readable recording medium containing a device driver program for enabling a data processing device to control a display device which is connected data-exchangeably therewith and has an intermission driving mode, in which the display device drives a display section in such a manner that a refreshing period during which an image displayed in the display section is refreshed and a non-refreshing period during which an image displayed in the display section is not refreshed are alternated with each other, the program causing a processor in the data processing device to execute:
• an update detection step of detecting an update of image data in an image buffer in a memory section within the data processing device, the memory section being capable of storing image data for a plurality of frames each representing an image to be displayed in the display section, the memory section having, as the image buffer, a memory area including at least one frame buffer area;
• an updated-data transfer step of transferring image data stored in the image buffer to the display device by a first-in first-out method upon detection of a data update in the image buffer;
• an intermission step of assuming an intermission state for an intermission period determined as the non-refreshing period at most, upon detection of a non-update of the image data in the image buffer for a predetermined time;
• a buffer extension step of extending the memory area of the image buffer upon shifting to the intermission state;
• a return instruction step of sending a return instruction for operating a stopped circuit in the display device to the display device, upon detection of a data update in the image buffer in the intermission state;
• and
• a return-to-normal-state step of returning to a normal state, in which the image data is transferred to the display device in response to a data update detected in the update detection step, upon detection of a data update in the image buffer in the intermission state.