Raster engine with hardware cursor

• US 7,808,448 B1
• Filed: 10/24/2006
• Issued: 10/05/2010
• Est. Priority Date: 09/28/2000
• Status: Expired due to Fees

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Dotson, Gary Dan
• Primary Examiner(s): Abdulselam; Abbas I
• Application Number:
  US11/552,319
• Time in Patent Office: 1,442 Days
• Field of Search: 345/204, 345/1.3, 345/3.1, 345157-161, 715856-858, 455/566, 455/575.3, 725/135
• US Class Current: 345/1.3
• CPC Class Codes: G09G 2310/0221 with use of split matrices G09G3/3644 and G09G3/3666 take precedence
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2340/0464 Positioning
• CPC Class Codes: G09G 2340/125 wherein one of the images is motion video
• CPC Class Codes: G09G 2370/045 using multiple communication channels, e.g. parallel and serial
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/08 Cursor circuits
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence

Abstract

An improved raster engine adapted to render video data from a frame buffer to one of a plurality of disparate displays is disclosed which comprises an integral bounded video signature analyzer, a hardware cursor apparatus supporting dual scanned displays, programmatic support for multiple disparate display types, multi-mode programmable hardware blinking, programmable multiple color depth digital display interface, and programmable matrix controlled grayscale generation.

Claims

1. A video controller for interfacing a frame buffer to a dual scan display, the video controller comprising:

a raster engine that receives video data from the frame buffer, formats the video data, and renders the formatted data to the dual scan display line by line; and

a hardware cursor that selectively overlays a cursor image across a display boundary onto adjacent first and second display portions of the dual scan display when the cursor crosses the display boundary.

2. The video controller of claim 1, the raster engine comprises a first data path and a second data path, the first and second data paths are respectively associated with the first and second display portions of the dual scan display.

3. The video controller of claim 2, the hardware cursor selectively inserts first portion cursor data associated with the first portion of the cursor image into the first data path of the raster engine as the first display portion is scanned out.

4. The video controller of claim 3, the hardware cursor selectively inserts second portion cursor data associated with the second portion of the cursor image into the second data path of the raster engine.

5. The video controller of claim 1, the dual scan display is refreshed by scanning out the first and second display portions simultaneously in parallel.

6. The video controller of claim 1, the raster engine comprises a vertical counter with a first vertical counter value and a second vertical counter value, the first and second vertical counter values respectively indicate first and second lines of formatted data rendered to the first and second display portions respectively, and a horizontal counter with a horizontal counter value that indicates a column of formatted data being rendered to the display.

7. The video controller of claim 6, the hardware cursor comprises:

a first and a second cursor start address registers with the first and second cursor start addresses respectively that indicate a first and a second cursor portion starting line in the respective first and second display portions;

a first and a second cursor portion height registers with respective first and second cursor portion height values that indicate a first and a second cursor portion heights;

a cursor column register with a cursor column start value; and

a cursor image width register with a cursor image width value that indicates a cursor image width.

8. The video controller of claim 7, the hardware cursor comprises a cursor state machine that compares:

the first vertical counter value with the first cursor start address and the first cursor portion height value;

the second vertical counter value with the second cursor start address and the second cursor portion height value; and

the horizontal counter value with the cursor column start value and the cursor image width value.

9. The video controller of claim 8, the hardware cursor comprises a cursor line buffer that selectively inserts first portion cursor data associated with a first portion of the cursor image into a first data path of the raster engine according to the comparison of the first vertical counter value with the first cursor start address and the first cursor portion height value and the comparison of the horizontal counter value with the cursor column start value and the cursor image width value, and selectively inserts second portion cursor data associated with a second portion of the cursor image into a second data path of the raster engine according to the comparison of the second vertical counter value with the second cursor start address and the second cursor portion height value and the comparison of the horizontal counter value with the cursor column start value and the cursor image width value.

10. A method of overlaying a cursor image onto a dual scan display in a video controller for interfacing a frame buffer to a dual scan display having adjacent first and second display portions with a display boundary therebetween, the method comprising:

rendering video data from the frame buffer to the dual scan display using a raster engine;

determining if a cursor image crosses a display boundary between a first display portion and a second display portion according to a cursor position of a hardware cursor;

selectively overlaying the cursor image onto at least one of the first display portion or the second display portion based on the cursor position.

11. The method of claim 10, further comprising:

determining if the cursor image is in the first display portion or the second display portion when the cursor image does not cross the display boundary; and

selectively overlaying the cursor image onto a first display portion or a second display portion based on the determination of a respective display portion.

12. The method of claim 10, further comprising:

determining a first portion and a second portion of the cursor image when the cursor image crosses the display boundary;

selectively overlaying the first and second portions of the cursor image across the display boundary onto the first and second display portions respectively according to the cursor position.

13. The method of claim 12, wherein determining a first portion of the cursor image comprises:

comparing a first vertical counter value in the raster engine with a first cursor start address and a first cursor portion height value in the hardware cursor; and

comparing a horizontal counter value in the raster engine with a cursor column start value and a cursor image width value in the hardware cursor.

14. The method of claim 13, wherein overlaying the first portion of the cursor image onto the first display portion comprises selectively inserting first portion cursor data associated with the first portion of the cursor image into a first data path of the raster engine according to the comparison of the first vertical counter value with the first cursor start address and the first cursor portion height value and the comparison of the horizontal counter value with the cursor column start value and the cursor image width value.

15. The method of claim 12, wherein determining a second portion of the cursor image comprises:

comparing a second vertical counter value in the raster engine with a second cursor start address and a second cursor portion height value in the hardware cursor; and

comparing the horizontal counter value in the raster engine with the cursor column start value and the cursor image width value in the hardware cursor.

16. The method of claim 15, wherein overlaying the second portion of the cursor image onto the second display portion comprises selectively inserting second portion cursor data associated with the second portion of the cursor image into a second data path of the raster engine according to the comparison of the second vertical counter value with the second cursor start address and the second cursor portion height value and the comparison of the horizontal counter value with the cursor column start value and the cursor image width value.

17. A system for interfacing a frame buffer to a dual scan display having adjacent first and second display portions with a display boundary therebetween, comprising:

means for receiving video data and displaying the video data on the dual scan display;

means for determining whether a cursor image crosses the display boundary according to a cursor position; and

means for selectively overlaying the cursor image onto at least one of the first display portion or the second display portion based on the cursor position.

18. The system of claim 17, the means for selectively overlaying the cursor image inserts first portion cursor data associated with a first portion of the cursor image into a first data path of the means for receiving and displaying the video data and the first display portion is scanned out and second portion cursor data associated with a second portion of the cursor image into a second data path of the means for receiving and displaying the video data.

19. The system of claim 17, further comprising means for indicating first and second lines of formatted data being rendered to the first and second display portions and a means for indicating column of formatted data being rendered to the display.

20. The system of claim 17, further comprising:

means for indicating a first cursor portion starting line in the first display portion;

means for indicating a second cursor portion starting line in the second display portion;

means for indicating a first cursor portion height;

means for indicating a second cursor portion height;

means for indicating a cursor column start value; and

means for indicating a cursor image width.

21. The system of claim 20, comprising means for comparing a first and second vertical counter values with a respective cursor start addresses and the respective cursor portion height value.

22. The system of claim 21, wherein the means for overlaying the first portion of the cursor image onto the first display portion comprises means for selectively inserting first portion cursor data associated with the first portion of the cursor image into a first data path of the means for receiving and displaying the video data according to the comparison of the first vertical counter value with the first cursor start address and the first cursor portion height value and the comparison of the horizontal counter value with the cursor column start value and the cursor image width value.

23. The system of claim 22, wherein the means for overlaying the second portion of the cursor image onto the second display portion comprises means for selectively inserting second portion cursor data associated with the second portion of the cursor image into a second data path of the means for receiving and displaying the video data according to the comparison of the second vertical counter value with the second cursor start address and the second cursor portion height value and the comparison of the horizontal counter value with the cursor column start value and the cursor image width value.