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  1. #1
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    8257 dma controller

    Hi everybody,
    I am working on a project, design of a DMA controller for 8086 processor. I am a newbie with assembly language programming.
    Do I need a 8086 processor for this project? I also downloaded a flat assembler for my coding needs. Any guidance as to how to start off on the project and online documentation which I could use for the project is greatly appreciated.

    Thanks

    •   Alt9th June 2009, 22:44

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  2. #2
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    dma controller 8257

    Can't recall the part number but intel makes a DMA IC for the 8086.


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    •   Alt10th June 2009, 15:25

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  3. #3
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    8086 dma controller

    Quote Originally Posted by blueroomelectronics
    Can't recall the part number but intel makes a DMA IC for the 8086.
    Well, in this project, as far as I can gather, I would write assembly language code to design DMA. This is an academic project. Since am a complete newbie with such projects, I wanted to know the tools that I would require. Please provide guidance and thank you very much in advance. I greatly appreciate any help and guidance.



    •   Alt11th June 2009, 03:47

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  4. #4
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    8086 processor

    To read how a DMA controller works, you might want to search for the 8257 Intel DMA controller, which was designed to work with the 8086.
    If you intend to write assembly code, yes you need an 8086 or some other processor to execute the instructions. A DMA controller has registers and transfers data from a source address to a target address without the interaction of a CPU, once the transfer is initiated. Basically the DMA controller "owns" the databus for a limited time. You can not really emulate a DMA controller in software because that is nothing else but a regular software controlled data transfer. With a DMA, the data transfer is hardware controlled
    hth, Bob


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