Previously, in MIG 7 Series v1.2, Read Data Banks required a PHASER_OUT driven by CQ# to drive the CLKB input to the ILOGIC shown in Figure 2-30 in UG586.
Starting with MIG 7 Series v1.3, the CPT_CLK_CQ_ONLY parameter was added and set to TRUE by default, which changes the CQ/CQ# functionality so that the PHASER_OUTs are no longer needed in the Read Data Banks, and their corresponding placement constraints are now removed from the UCF.
In MIG 7 Series v1.4, there is a known issue where the PHASER_OUTs are still enabled and used regardless of what CPT_CLK_CQ_ONLY is set to, and in some cases the following error can occur:
ERROR: [Place-370] An unconstrained Phaser instance has been found. Phaser instances and their associated I/O logic must be LOC constrained to a legal site locations for placement to succeed. Check to see whether all core constraints were properly used or manually add LOC constraints for the following instance(s). Unconstrained Phaser instance(s): Inst 'u_qdr_a_14/u_qdr_phy_top/u_qdr_rld_mc_phy/qdr_rld_phy_4lanes_2.qdr_rld_phy_4lanes/qdr_rld_byte_lane_D.qdr_rld_byte_lane_D/PHASER_OUT_inst.phaser_out'
This is a result of the PHASER_OUTs not being constrained in the UCF.
To work around the error, the user must manually add the missing PHASER_OUT constraints into the UCF, for example: