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Altera_Forum's avatar
Altera_Forum
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17 years ago

Instantiation of DMA on SOPC Builder

Hello,

I have a question about instantiation of DMA in SOPC Builder. When you add the DMA controller, you must connect the read master and the write master. For me, I can connect them to any white circle of the two columns on the right (see sopc 2.jpg) because they all are linked to the data bus. So it is the same connection if I want to do a transfer from memory to memory, or from memory to a peripheral (like an UART), is it right ?

Thank in advance.

Jérôme

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    The instruction master is only capable of reading instructions (code) from memory. It's not capable of write accesses since that's what the data master is for. As a result if you don't plan on placing code in a particular memory then there is no need to connect the instruction master up to it.

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    correct !

    both pictures show what you described

    and yes you correctly connected the control port, no need to connect to the instruction master.

    i see no mistakes.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    each white dot means that this master can not reach the slave.

    if you change such a dot to a black dot, then the master can access this particular slave.

    you must specify the allowed / possibel connection

    the read master connects to each possible source

    the write master to each possible destination

    but you must enable the controlport slave for the nios data master otherwise you wont be able to control the dma by software.