Access device for direct memory access and method for implementing single channel bidirectional data interaction

Abstract

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 present invention relates to direct memory access technology, in particular to a direct memory access device and a method for realizing single-channel two-way data interaction. Background technique [0002] Direct Memory Access (DMA, Direct Memory Access) is an important technology to improve the efficiency of data transmission in a microcomputer system. DMA technology can realize the movement and exchange of data between different areas of the storage space. This type of access generally does not require a CPU. The intervention of the DMA controller completes all the control. Specifically: In a system that supports DMA for data transmission, both DMA and CPU are connected to the system bus. Generally, the CPU controls the system bus. DMA is only a controlled module that works in a slave state, and DMA is used. The method of data transmission is to replace the CPU with the DMA to obtain the control of the system bus within a certain period of time, and ...

AI Technical Summary

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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