Display controller, electronic instrument, and method of supplying image data

• US 20060001671A1
• Filed: 07/05/2005
• Published: 01/05/2006
• Est. Priority Date: 07/05/2004
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Fukuda, Taketo, Kamijo, Hirofumi
• Granted Patent: US 7,667,708 B2
• Time in Patent Office: Days
• US Class Current: 345/531
• CPC Class Codes: G06F 12/0207 with multidimensional access, e.g. row/column, matrix
• CPC Class Codes: G06F 12/06 Addressing a physical block of locations, e.g. base addressing, module addressing, memory dedication G06F12/08 takes precedence
• CPC Class Codes: G09G 2340/0492 Change of orientation of the displayed image, e.g. upside-down, mirrored
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: G09G 5/39 Control of the bit-mapped memory

Abstract

A display controller includes a memory storing at least three frames of image data, a write starting address register to which a write starting address is set, a read starting address register to which a read starting address is set, and a rotation control section performing control for reading out from the memory image data corresponding to an image whose orientation is rotated. When writing of the image data to the area designated by the write starting address is completed, the write starting address is updated and the previous value of the updated write starting address is set to the read starting address register. The image data corresponding to the rotated image is read out by the rotation control section 40 from an area of the memory designated by the read starting address, and then supplied to a display driver.

Claims

1. A display controller for supplying image data to a display driver for driving a display panel, comprising:

a memory storing at least three frames of image data;

a write starting address register to which a write starting address for writing image data in the memory is set;

a read starting address register to which a read starting address register for reading out image data to be supplied to the display driver from the memory is set; and

a rotation control section performing control for reading out image data obtained by rotating the orientation of an image by reading out image data for each pixel stored in the memory in an order corresponding to the rotational angle, wherein

when writing of image data to the area designated by the write starting address is completed, the write starting address set in the write starting address register is updated with a write starting address for writing image data of the succeeding frame, and the previous value of the updated write starting address is set to the read starting address register as the read starting address, and

image data corresponding to the rotated image and read out by the rotation control section from an area of the memory designated by the read starting address is supplied to the display driver.

2. The display controller according to claim 1, wherein

the read starting address is not updated until reading of one frame of image data from the area of the memory designated by the read starting address is completed.

3. The display controller according to claim 1, further comprising:

a sync signal generation circuit generating a vertical sync signal defining a scanning period of one frame, wherein

if the image data is supplied to the display driver in sync with the vertical sync signal, the previous value of the updated write starting address is set to the read starting address register as the read starting address in sync with the vertical sync signal upon completion of writing of the image data.

4. The display controller according to claim 3, wherein

providing the vertical sync signal becomes active at least two times after completion of writing of the image data, the previous value of the updated write starting address is set to the read starting address register as the read starting address.

5. The display controller according to claim 3, wherein

a rate of writing one frame of image data to the memory is lower than a rate of reading out the rotated image data from the memory.

6. The display controller according to claim 1, wherein

the write starting address is set in the write starting address register for each writing area of the memory, the writing area corresponding to a frame, and either one of the write starting addresses is selected upon writing the image data.

7. The display controller according to claim 1, further comprising:

a host interface performing an interfacing process with a host, wherein

a first interrupt indicating completion of writing of the image data is reported to the host, and

the previous value of the updated write starting address is supplied as the read starting address by the host reported with the first interrupt via the host interface.

8. The display controller according to claim 7, wherein

the updated write starting address is supplied by the host reported with the first interrupt via the host interface.

9. The display controller according to claim 7, wherein

a second interrupt indicating that the vertical sync signal becomes active is reported to the host, and

providing the first and the second interrupts are reported, the previous value of the updated write starting address is supplied as the read starting address by the host via the host interface.

10. The display controller according to claim 1, further comprising:

a display driver interface for supplying the display driver with image data read out from the memory.

11. An electronic instrument, comprising:

a display panel;

the display controller according to claim 1;

and

a display driver driving the display panel in accordance with image data supplied by the display controller.

12. The electronic instrument according to claim 11, further comprising:

a host inputting/outputting image data from/to the display controller.

13. A method of supplying image data to a display driver for driving a display panel, comprising:

writing image data to a part of an area of a memory storing at least three frames of image data, the part of the area being designated by a write starting address set in a write starting address register;

setting the write starting address to a read starting address register upon completion of writing of the image data, the read starting address register storing a read starting address for reading out from the memory image data to be supplied to the display driver; and

reading out image data of each pixel from an area of the memory designated by the read starting address set in the read starting address register in an order corresponding to a rotational angle to supply to the display driver as rotated image data obtained by rotating the orientation of an image.

14. The method according to claim 13, wherein

the read starting address is not updated until reading of one frame of image data from the area of the memory designated by the read starting address is completed.

15. The method according to claim 13, wherein

if the image data is supplied to the display driver in sync with the vertical sync signal defining a scanning period of one frame, the write starting address is set to the read starting address register as the read starting address in sync with the vertical sync signal upon completion of writing of the image data.

16. The method according to claim 15, wherein

when the vertical sync signal becomes active at least two times after completion of writing of the image data, the write starting address is set to the read starting address register as the read starting address.

17. The method according to claim 15, wherein a rate of writing one frame of image data to the memory is lower than a rate of reading out the rotated image data from the memory.