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Ok, so I will connect resistors to lower voltage, I think
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A resistive divider should be ok if you are driving a signal from the DE1 to the 1.8V logic, however, the 1.8V logic will not be able to drive a valid high back to the 3.3V logic. For that, you need a level translator.
If you were designing your own FPGA board, then you could power a VCCIO bank at 1.8V and connect it directly to your 1.8V logic. However, the DE1 does not provide a 'simple' way of changing the VCCIO. I did notice that there was a jumper from VCC33 to VCCIO. You could remove that and power VCCIO from 1.8V, but since there is already logic on that power rail, the other components would stop working (which you might not care about).
Cheers,
Dave
Honored Contributor
