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US5907330A
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Reducing power consumption and bus bandwidth requirements in cellular phones and PDAS by using a compressed display cache
Assignee: Intel Corp
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Filing: 1996-12-18
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Granted: 1999-05-25
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Expires: 2016-12-18
Abstract
Abstract A method and apparatus for reducing power consumption and system bus load caused by a display controller in a unified memory system. A compression engine monitors a bus over which display data from the unified memory flows. The compression engine captures and compresses a copy of the display data corresponding to a display frame. The compressed data is stored in a small memory unit. Subsequent refreshes of the display are serviced by a decompression engine. The decompression engine decompresses the compressed data from the small memory unit and provides the decompressed data to the display controller.
Inventors
- 👤 Charles R. Simmers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:41
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/36; G09G5/363; G09G2330/00; G09G2330/02; G09G2330/021; G09G2340/00; G09G2340/02; G09G2360/00; G09G2360/12; G09G2360/125; H; H04; H04W; H04W52/00; H04W52/02; H04W52/0209; H04W52/0261; H04W52/0267; H04W52/027; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
146 words
A system having no dedicated frame buffer comprising: a system bus; a host processor coupled to the system bus; a main memory coupled to the system bus and having a frame buffer implemented therein; a display controller coupled to the system bus; a display coupled to the display controller; a compression engine coupled to the system bus, the compression engine to capture and compress a copy of display data directed to the display controller from the main memory; a storage unit coupled to the compression engine storing data captured and compressed by the compression engine; a decompression engine coupled to the display controller and the storage unit, the decompression engine decompressing data from the storage unit and transmitting the data to the display controller; and wherein the main memory can be placed in a reduced power state even though the display controller periodically refreshes the display.
Claim 2
Independent Claim
146 words
A system having no dedicated frame buffer comprising: a system bus; a host processor coupled to the system bus; a main memory coupled to the system bus and having a frame buffer implemented therein; a display controller coupled to the system bus; a display coupled to the display controller; a compression engine coupled to the system bus, the compression engine to capture and compress a copy of display data directed to the display controller from the main memory; a storage unit coupled to the compression engine storing data captured and compressed by the compression engine; a decompression engine coupled to the display controller and the storage unit, the decompression engine decompressing data from the storage unit and transmitting the data to the display controller; and wherein the main memory can be placed in a reduced power state even though the display controller periodically refreshes the display.
Claim 3
Dependent Claim
24 words
The system of claim 1 wherein the compression engine captures display data when a frame buffer dirty bit is set to a predetermined value.
Claim 4
Dependent Claim
29 words
The system of claim 1 wherein the compression engine does not capture display data even though a frame buffer dirty bit is set while a second predetermined condition exists.
Claim 5
Dependent Claim
20 words
The system of claim 1 wherein the storage unit is sized to contain exactly one frame of compressed display data.
Claim 6
Dependent Claim
31 words
The system of claim 1 wherein the display controller refreshes the display using the data provided by the decompression engine such that the main memory is not used during a refresh.
Claim 7
Dependent Claim
31 words
The system of claim 1 wherein the decompression engine transmits data to the display controller over dedicated lines, thereby reducing demand by the display controller for bandwidth on the system bus.
Claim 8
Independent Claim
109 words
A method of reducing power consumption in a computer system having a frame buffer implemented as part of a unified memory, the method comprising: capturing a frame of display data from a bus as the frame is transmitted from the frame buffer to a display controller; compressing the frame of display data captured from the bus; storing the frame in a compressed form in a small storage unit; decompressing the compressed form from the small storage unit to refresh a display while an image on the display remains static; and placing the unified memory in a reduced power state while the display is refreshed from the small storage unit.
Claim 9
Independent Claim
109 words
A method of reducing power consumption in a computer system having a frame buffer implemented as part of a unified memory, the method comprising: capturing a frame of display data from a bus as the frame is transmitted from the frame buffer to a display controller; compressing the frame of display data captured from the bus; storing the frame in a compressed form in a small storage unit; decompressing the compressed form from the small storage unit to refresh a display while an image on the display remains static; and placing the unified memory in a reduced power state while the display is refreshed from the small storage unit.
Claim 10
Dependent Claim
28 words
The method of claim 7 wherein the step of compressing comprises the step of: reducing a number of bits from which a pixel of display data is derived.
Claim 11
Dependent Claim
22 words
The method of claim 7 wherein the step of capturing is performed transparently to both a host processor and a display controller.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-05-24 | 2002-11-23 | 2003-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-24 | 2006-11-23 | 2007-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-24 | 2010-11-23 | 2011-05-25 | $7700.00 | Window Closed / Lapsed |