Access device for direct memory access and method for implementing single channel bidirectional data interaction
A memory and channel technology, applied in memory systems, electrical digital data processing, instruments, etc., can solve problems such as inability to realize effective utilization of memory resources, limit DMA peripheral resources, increase chip area, etc., and achieve simple design and memory saving Space, the effect of improving the utilization rate
Inactive Publication Date: 2007-12-12
HUAWEI TECH CO LTD
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Problems solved by technology
Due to the limited channel resources of DMA, this limits the peripheral resources supported by DMA
If the peripherals supported by DMA are increased by increasing the number of DMA channels, more circuits will be introduced to increase the area of the chip, thereby increasing the cost of the chip
[0017] 2) During the DMA transfer process from the memory to the peripheral, two memory RAMSRC0 and RAM SRC1 of the same size are required to update and send data in a ping-pong switching mode; The memory RAM DST0 and RAM DST1 process the latest received data in a ping-pong switching mode, which cannot realize the effective use of memory resources
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[0050] The core idea of the present invention is: improve the channel logic and the structure of each channel of the register group in the DMA, replace the FIFO control logic with the ping-pong operation structure, and realize the operation of data in different flow directions through the ping-pong switching, so that each independent channel of the DMA Both can complete data reading and writing between peripherals and memory at the same time, forming a double DMA (DDMA, Duplicated DMA) structure.
[0051] In order to support the realization of the DDMA function, the DMA of the present invention has carried out two improvements to the existing DMA: first, a group of control registers is added corresponding to each channel; secondly, the realization structure of each DMA channel control logic is changed, and corresponding modification Structure of the channel control logic. Specifically: First, add four control registers for each channel, which respectively store the source ad...
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The invention discloses a direct memory access (DMA) device, comprising bus Slave interface, DMA request and response interface, bus Master interface, control logic and register set, channel logic and register set, and interrupt request logic, where the key point is that control logic of each DMA channel in the channel logic and register set comprises: channel control logic used to control state switching of first and second state selection units and control read-in / -out of data from source address to destination address; first and second data buffer areas for storing data read in DMA channels in different directions; first and second state selection units for reading data from the source address into the first or second data buffer area and sending data in the second or first data buffer area to the destination address. And the invention also discloses a method for realizing single channel bidirectional data exchange. And the device and method can make each DMA channel support bidirectional data exchange, raising resources utilization ratio and DMA operating efficiency and reducing cost of DMA chip.
Description
technical field [0001] The invention relates to direct memory access technology, in particular to a direct memory access device and a method for realizing single-channel bidirectional data interaction. Background technique [0002] Direct memory access (DMA, Direct Memory Access) is an important technology to improve data transmission efficiency in microcomputer systems. DMA technology can move and exchange data between different areas of storage space. This kind of access generally does not require CPU The intervention of the DMA controller to complete all the control. Specifically: In a system that supports DMA to realize data transmission, both DMA and CPU are connected to the system bus. Generally, the CPU controls the system bus, and DMA is only a controlled module that works in a slave state. The data transmission achieved by means of DMA means that within a certain period of time, the DMA replaces the CPU to obtain the control of the system bus, and takes out or save...
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IPC IPC(8): G06F13/00G06F13/14G06F12/00
Inventor 马涛
Owner HUAWEI TECH CO LTD