Method for transferring DMA data in a multimedia intergrated circuit including preloading DMA instructions in a frame buffer

• US 6,145,025 A
• Filed: 08/19/1997
• Issued: 11/07/2000
• Est. Priority Date: 08/20/1996
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lim, Kyu-Tae
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): KIM, HAROLD J
• Application Number:
  US08/912,814
• Time in Patent Office: 1,176 Days
• Field of Search: 395/842-848, 395/849-855, 710/22, 710/23, 710/24, 710/25, 710/26, 710/27, 710/28, 710/29, 710/30, 710/31, 710/32, 710/33, 710/34, 710/35
• US Class Current: 710/22
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence

Abstract

A method for transferring DMA data between the video port and the host interface in a multimedia processor is disclosed. The method includes determining whether one frame data should be transferred between the host interface and the video port; preloading some DMA instructions in the frame buffer and setting the DMA register to be fitted for the DMA operation; and fetching the preloaded instructions from the frame buffer subsequently by the DMA controller to perform video data transfer at a predetermined data bandwidth. According to this invention, the time consumption of a microprocessor for programming the DMA controller is reduced, thereby enhancing the data transfer rate between the host interface and video port of the multimedia computer system.

Claims

1. A method for transferring DMA data in a multimedia processor, comprising:

determining whether frame data should be transferred between a host interface and a video port;

preloading DMA instructions into a frame buffer and setting a DMA register to be fitted for DMA operation when said determining determines frame data should be transferred,

the preloading of DMA instructions and setting the DMA register comprising

setting a source/destination register,

setting a transfer count register, and

setting a DMA start enable register by writing a DMA start instruction into the DMA controller;

fetching the preloaded DMA instructions from the frame buffer, said fetching consisting essentially of fetching only one DMA instruction from the frame buffer for each transfer; and

transferring video data by a DMA controller at a predetermined data bandwidth.

2. The method for transferring DMA data as recited in claim 1, wherein the preloading is started in response to an interrupt signal invoked by a video controller.

3. The method for transferring DMA data as recited in claim 1, further comprising writing the preloaded DMA instructions in an off-screen area of the frame buffer by a frame buffer controller.

4. The method for transferring DMA data as recited in claim 1, wherein the fetching of the preloaded instructions includes:

determining whether the transfer count has ended;

determining whether a DMA instruction is fetchable; and

enabling the DMA controller to transfer the video data from source to destination.

5. The method for transferring DMA data as recited in claim 1, wherein the transferring includes transferring a plurality of data, each transfer of data requiring a corresponding instruction and the preloading includes preloading more than one instruction into the frame buffer.

6. The method for transferring DMA data as recited in claim 1, wherein the transferring includes transferring a plurality of data, each transfer of data requiring a corresponding instruction and the preloading includes preloading all instructions required for transferring the plurality of data into the frame buffer.

7. The method for transferring DMA data as recited in claim 1, wherein said transferring video data includes only a single interruption of the host interface.

8. The method for transferring DMA data as recited in claim 1, further comprising, after said transferring is complete, returning to said determining.

9. In a multimedia processor for simultaneously handling a wide assortment of multimedia tasks and comprising a host interface, a DMA register, a frame buffer controller coupled with a frame buffer, and a video port coupled with external video system, wherein a DMA operation is performed to move data between the video port and the host interface, a method for transferring DMA data comprising:

determining whether frame data should be transferred between the host interface and the video port;

preloading DMA instructions in the frame buffer and setting the DMA register to be fitted for the DMA operation when said determining determines frame data should be transferred, the setting of the DMA register comprising

setting the source/destination register,

setting a transfer count register, and

setting a DMA start enable register by writing a DMA start instruction into the DMA controller; and

fetching the preloaded instructions from the frame buffer subsequently by a DMA controller to perform video data transfer at a predetermined data bandwidth, wherein said fetching consists essentially of fetching only one DMA instruction from the frame buffer for each transfer.

10. The method for transferring DMA data as recited in claim 9, further comprising starting the preloading in response to an interrupt signal invoked by a video controller.

11. The method for transferring DMA data as recited in claim 9, wherein the preloaded DMA instructions are written in the off-screen area of the frame buffer by the frame buffer controller.

12. The method for transferring DMA data as recited in claim 9, wherein the fetching of the preloaded instructions includes;

determining whether the transfer count has ended;

determining whether a DMA instruction is fetchable; and

enabling the DMA controller to transfer the video data from source to destination.

13. The method for transferring DMA data as recited in claim 9, wherein the transferring includes transferring a plurality of data, each transfer of data requiring a corresponding instruction and the preloading includes preloading more than one instruction into the frame buffer.

14. The method for transferring DMA data as recited in claim 9, wherein the transferring includes transferring a plurality of data, each transfer of data requiring a corresponding instruction and the preloading includes preloading all instructions required for transferring the plurality of data into the frame buffer.

15. The method for transferring DMA data as recited in claim 9, wherein said video data transfer includes only a single interruption of the host interface.

16. The method for transferring DMA data as recited in claim 9, further comprising, after said video data transfer is complete, returning to said determining.