DUAL_PURPOSE_CLOCK_PIN_DELAY issue on Cyclone IV E

Hi All,

I am currently implementing my own mobile DDR-SDRAM controller and I am encountering some issue.

Indeed, during a read from the external memory, I want to delay the data strobe (DQS) to be able to correctly capture the data (DQ). In order to do this, I use the following assignment to add a delay on DQS line:

set_instance_assignment -name DUAL_PURPOSE_CLOCK_PIN_DELAY 8 -to lpddr_dqs

The problem I have is that Quartus does not report any delay at all. But it doesn't ignore the constraint either. I was expecting to see some delay in the" fitter/Resource Section/Delay Chain Summary" but all the delays seem to be fixed at 0 ns.

Does someone know where we can check the actual value of this delay? Or is there a problem with my way of doing things?

Thanks a lot in advance!