OCT Termination - how many pins?

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Hello

With more pins I get the following Error:

Error (176210): Can't place pin RAM2_DQB[1] with I/O standard 2.5 V, Termination setting Off, and PCI I/O setting on due to device constraints

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Hi Robert, are pin on supported side/bank?

From user manual cyiv-51006.pdf you can find here https://www.altera.com/products/fpga/cyclone-series/cyclone-iv/features.html

bottom of page right column "connectivity" line I/O Features (pdf)

at page 8 we read:

cyclone iv devices support r s oct with calibration in the top, bottom, and right i/o

banks. the r s oct calibration circuit compares the total impedance of the i/o buffer

to the external 25 ohm ±1% or 50 ohm ±1% resistors connected to the rup and rdn pins, and

dynamically adjusts the i/o buffer impedance until they match (as shown in

figure 6–2).

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Error (176210): Can't place pin RAM2_DQB[1] with I/O standard 2.5 V, Termination setting Off, and PCI I/O setting on due to device constraints

What´s the reason for that?

If I assign no oct termination, the design dose fit.

How many pins can use the oct feature?

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http://quartushelp.altera.com/14.0/mergedprojects/msgs/msgs.htm

insert your error number, the error appear under the search pane then click on it and read the help about constraint.

Or faster from quartus click on error to go to this help page.

If this doesn't help please post pin assignment.

Best regards