DDR2 UNIPHY IP cal_fail is asserted

I connected RUP and RDN to two pins, these two pin, one of them has 50 ohm pull up and another has 50 ohm pull dwon.

But I found that local_cal_fail is asserted in signalTAP.

I checked all pin allocation are corrected, clock input is 100 MHz, and memory bus clock is 200MHZ.

could some one give some suggestions for this issue?