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Altera_Forum
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11 years ago

Vref

Hi I haven't fully understood the concept of the VREF pins. I know this is the threshold voltage at which a voltage referenced IO standard decides between a low or high. But isn't this just...
Altera_Forum's avatar
Altera_Forum
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10 years ago

FYI, the VREF is for INPUT only. You can imagine the INPUT buffer is like a comparator. It will need a reference to know what is defined as HIGH or LOW. Normally VREF is set in the middle so that it HIGH/LOW is equally divided across its range of voltage.