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What is a DMA and how to design a DMA controller?

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billjoe

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[HELP] What is DMA ?

I am a new guy for logic design
I start to design a DMA controller
may I ask
The principle of DMA?
How to design a DMA controller?
 

xuanzhu

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[HELP] What is DMA ?

DMA is direct memory access
its intent is to reduce the cpu interference to data transfer. you can download some information documents and code file about it at opencore
 

ami

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Re: [HELP] What is DMA ?

DMA operation:
--------1.CPU tells DMA controller: Read/Write,Device address,Starting address of memory block for data,Amount of data to be transferred
--------2.CPU carries on with other work
--------3.DMA controller deals with transfer and takes over bus for a cycle
--------4.DMA controller sends interrupt when finished
 

vivek

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Re: [HELP] What is DMA ?

DMA helps in directly accessing memory without burdening the processor. DMA will take care of all read/write transfers to/from memory.

The communication between processor and DMA can be based on any protocol like request-grant technique. DMA controllers usually have multiple output banks/ports which support many no of memory. if u r new to DMA the data sheet of INTEL 8237 DMA controller shall be a good starting point.
 

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