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Altera_Forum's avatar
Altera_Forum
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19 years ago

mutiple DMA instantiations

Hi, In my system I want to have DMA access between the following componenets 1) SDRAM <-> Ethernet(LAN91C111) 2) SDRAM <-> UART 3) SDRAM <-> On-Chip Memory 4) SDRAM <-> USB 5) SDRAM <-> ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

1) Will this cause problems --> no

2) Does this have any advantages --> in your case no

3) Best practices... see below

Having multiple DMA engines in your design is beneficial if you expect to be able to run them in parallel. In your case you have everything transferring to/from SDRAM. Since that&#39;s a single Avalon-MM slave port, parallel accesses are not possible.

Are you sure you don&#39;t want to use the DMA only between SDRAM and the onchip memory, Ethernet, and USB? Direct memory access engines typically have the most impact when connected to high throughput components (like the ones I just listed).