Impeller driven traveling sprinkler

• US 20020033812A1
• Filed: 09/18/2001
• Published: 03/21/2002
• Est. Priority Date: 09/18/2000
• Status: Active Grant

• Current Assignee: Mannesmann VDO AG (Continental AG)
• Original Assignee: Mannesmann VDO AG (Continental AG)
• Inventors: Van Vugt, Henricus Antonius Gerardus
• Granted Patent: US 6,791,538 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2360/125 using unified memory architecture [UMA]
• CPC Class Codes: G09G 5/399 using two or more bit-mapped memories, the operations of which are switched in time, e.g. ping-pong buffers

Abstract

A display-based system is disclosed with a processing unit, a memory control facility, and a graphics display controller interfacing to a display facility. Collectively these modules are interconnected by a bus facility to an external memory facility. The graphics display controller has a first mode providing a video image signal to the display facility. In particular, a detector is provided for detecting display stabilization. An output of the graphics display controller is being coupled to a frame grabber. The frame grabber is arranged to execute a writeback-to-memory storage of the video image signal into a writeback image memory during a subsequent videoframe, and subsequently signaling the graphics display controller to switch over to a second mode, in which the stored writeback video image signal is supplied to the display facility. The average data traffic on the bus facility is thus reduced.

Claims

1. A display-based system comprising:

a processing unit (22);

a memory control facility (32, 34);

a display facility (26);

a graphics display controller (24, 50) interfacing to the display facility and having a first mode supplying a video image signal including at least one overlay plane to the display facility;

a bus facility (20) collectively interconnecting the processing unit, the memory control facility, and the graphics display controller to an external memory facility (30);

a detector (22) for detecting display stabilization;

a frame grabber (28, 52);

the writeback image memory (Mn) coupled to the frame grabber; and

wherein an output of the graphics display controller (24, 50) is coupled to the frame grabber arranged for executing a writeback-to-memory storage of the video image signal into the writeback image memory (Mn) during a subsequent video frame, and subsequently signaling the graphics display controller (24, 50) to switch over to a second mode, in which the stored writeback video image signal is supplied to the display facility (26) for display.

2. The system as claimed in claim 1 where the frame grabber (28, 52) is arranged for on-the-fly compact coding of the video image signal into an encoded writeback video image signal, and the graphics display controller (24, 50) includes a decoding facility to arrange for decoding the encoded writeback video image signal prior to the display thereof.

3. The system as claimed in claim 2 wherein the coding is run-length encoding.

4. The system claimed in claim 1 wherein the detector (22) signals the graphics display controller (24, 50) to switch from the second mode to the first mode when a change in the video image signal to be displayed occurs.

5. The system as claimed in claim 1 wherein the processing unit (22), memory control facility (32, 34) and graphics display controller (24, 50) are contained in a single integrated circuit.

6. The system as claimed in claim 1 characterized by a use thereof in a car navigation application.

7. A system as claimed in claim 1 wherein signaling remains suspended until the start of a next video frame.

8. A system as claimed in claim 1 further comprising hardware for effecting signaling.

9. A method for operating a display system having a processing unit (22), a memory control facility (32, 34), and a graphics display controller (24, 50) interfacing to a display facility (26), the processing unit, memory control facility and graphics display controller collectively interconnected by a bus facility (20) to an eternal memory facility (30), the method comprising:

providing a first mode for providing a video image signal from the graphics display controller to the display facility;

generating a screen stable signal at a detection of display stabilization;

subsequently executing a writeback-to-memory storage of the video image signal into a writeback image memory (Mn) by frame grabber means (28, 52); and

signaling the graphics display controller (24, 50) to switch over to a second mode, in which the stored writeback video image signal is being supplied to the display facility (26) for display.

10. The method as claimed in claim 9, wherein the writeback-to-memory storage applies to a single video overlay plane.

11. The method as claimed in claim 9 wherein the screen stable signal is made inactive upon entering a graphics handler procedure, and is returned to active upon exiting the graphics handler procedure.

12. The method as claimed in claim 9 further comprising determining the screen stable signal through calculating a video check sum at an output of the graphics display controller (24, 50).

13. The method as claimed in claim 9 further comprising determining the screen stable signal through monitoring CPU accesses to memory regions that contain video data that are currently displayed.

14. The method as claimed in claim 9 wherein writeback-to-memory storage is performed during a succession of a plurality of frame intervals for constituting a single image.

15. A method as claimed in claim 9 wherein the graphics display controller (24, 50) is switched between the first and second modes during a vertical video signal blanking interval.