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Altera_Forum
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18 years ago

Problems about DDR2!

Error: Too many output and bidirectional pins in I/O bank 3 assigned near VREF pin AB11 (VREFGROUP_B3_N1) on device EP3C120F780C7 -- no more than 9 output and bidirectional pins allowed near the VREF...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
18 years ago

It looks like Quartus already told you what the problem is, you have more than 9 outputs associated with VRef pin AB11 (9 being the limit).

Open the Pin Planner and click on "Show VREF Groups" on the toolbar. Make sure you have maximum 9 output/bidir pins in each VCCIO group for all voltage referenced I/Os - if you have more than 9, you can swap them with inputs (or leave unassigned).

For more information, read the cyclone iii handbook - i/o features (http://www.altera.com/literature/hb/cyc3/cyc3_ciii51007.pdf), page 7-25.