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Altera_Forum's avatar
Altera_Forum
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15 years ago

Question regarding wm8731 audio on DE2-70

I have a question regarding the audio codec on the DE2-70 board. How is it possible to generate the proper clock frequency for the WM8731 codec from the 50MHz or 28.63MHz on-board oscillators? ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Okay, so I checked the example audio demonstration code for the DE2-70 that is provided with the board and the "audio_pll.v" file has an input frequency of 50MHz and an M/N of 4/11, which results in an 18.181818MHz clock.

So apparently Altera/Terasic (or whoever made the demonstration) also didn't deem it necessary to get an _exact_ 18.432MHz clock. So I guess that answers this riddle. Having an in-exact bit clock must just not be that big of a deal....weird. I don't understand it myself but then again I don't really need to. Haha.

Thanks!

Jonathon