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Instantiation of DMA on SOPC Builder

Altera_Forum
Honored Contributor II
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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
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Altera_Forum
Honored Contributor II
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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.
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Altera_Forum
Honored Contributor II
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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.
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Altera_Forum
Honored Contributor II
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Ok, many thanks.

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Altera_Forum
Honored Contributor II
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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.

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