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DMA data-transmission method and system

A data transmission method and data transmission technology, applied in the field of DMA data transmission, can solve problems affecting CPU work efficiency, achieve the effects of reducing occupation, saving bus resources, and improving work efficiency

Inactive Publication Date: 2009-06-10
北京红旗胜利科技发展有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, in order to ensure the effective transmission of data between the CPU and the DMA on the bus, no matter which of the above-mentioned DMA transmission methods is used, the DMA needs to return the bus control right to the CPU after the data transmission is completed, for example, notify the CPU in an interrupt mode. In this case, if the DMA needs to transfer multiple pieces of data, it will notify the CPU after each piece of data transmission, which greatly affects the working efficiency of the CPU.

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  • DMA data-transmission method and system

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Embodiment Construction

[0050] The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0051]The core idea of ​​the embodiment of the present invention is to set the DMA controller with units such as transmission, calculation update, judgment, and calculation inside the CPU, so that the alternation of access rights between the CPU and the DMA controller can be completed without using the bus. , saves bus resources, and realizes that the DMA controller interrupts the CPU once to complete the multi-segment data transmission, which improves the work efficiency of the CPU and DMA.

[0052] refer to figure 1 , which shows a flow chart of the steps of Embodiment 1 of a DMA data transmission method of the present invention, which may specifically include the follo...

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Abstract

The invention discloses a data transmission method for DMA, which comprises the following steps: S1, a CPU configures data transmission information of the DMA inside the CPU; S2, the DMA transmits first segment of data to a target address from a source address, and the length of the transmitted data satisfies an initial data length; S3, a transmission fragment number is updated, whether the updated transmission fragment number satisfies an end threshold is judged, the CPU is notified of the finishing of data transmission if the updated transmission fragment number satisfies the end threshold, and the following steps are executed if not so; S4, a source address and a target address of the transmission of next segment of data and the transmission length of the data are calculated; and S5, the transmission of the next segment of data is finished, and the operation returns to the step S3.

Description

technical field [0001] The present invention relates to the technical field of DMA data transmission, in particular to a DMA data transmission method and system. Background technique [0002] DMA (Direct Memory Access, direct memory access) refers to the direct transfer of data between the memory and the I / O device, which is a way of completely completing the input and output operations by hardware. When using DMA to transmit data, a special device is needed to coordinate the data transmission between the peripheral interface and internal memory. This special device is called DMA controller, or DMAC for short. The DMAC completely takes over the control of the bus from the CPU, and the data exchange does not go through the CPU, but directly between the memory and the I / O device. Inside the DMAC, there are several registers: the address register, which stores the address of the storage unit storing IO data during DMA transfer; the byte counter, which stores the number of byte...

Claims

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Application Information

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IPC IPC(8): G06F13/28
Inventor 石艳
Owner 北京红旗胜利科技发展有限责任公司