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Altera_Forum
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9 years ago

ALTDDIO_OUT primitive usage internally

Hi, I am using the Output DDR interface in one of my submodules in the hierarchy. I see that the output register is not set in spite of me selecting the option "Registers powerup high". Also, ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 years ago

This is meant to map to the IO cell DDR registers, and my experience is that it errors out if not hooked up to an output port. You should be able to do the same in RTL very easily. The main purpose is to make sure it uses the dedicated resources, especially the output mux, which inference tools have never been great at(not that it would be hard).