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Altera_Forum
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10 years ago

CYCLONE V OCT Problem

Hi, I am using in my design a Cyclone V device (namely the 5CGXBC3B7U15C8N), while using PIN#M13, N12 as an LVDS RX port. Going through ALTERA device handbook, it has two variations for On Ch...
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Altera_Forum
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10 years ago

You can adjust the On-Chip Termination (OCT) via this same 'Input Termination' parameter - various OCT options are available. However, I'm sure not all (if any) of the the OCT options will be valid for LVDS. I suspect you'll only be able to switch it OFF or leave it a it's default. Play around with it to see.

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what is the termination value if this resistor is missing?

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Something that's not correct. The handbook doesn't cover this eventuality. Unfortunately, if you've not followed the guidelines, you're on your own. However,

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Some specific DQ pins can also be used as RZQ pins. If you need extra RZQ pins, you can use these [the] DQ pins as RZQ pins instead.

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So, depending on your board you may be able to salvage something by using an alternative pin.

Cheers,

Alex