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AR# 57068

ERROR: [Place 30-433] received while doing manual placement of LUT using LOCK_PINS constraint.

Description

I am doing manual placement of LUTs using the "LOCK_PINS = ALL" property to achieve timing.

However, Vivado returns the following Error message in Place:

ERROR: [Place 30-433] Unplaced instances found.
One example is: '/../../u_dprdfixed/buf2fifo_n_low_00_05x' cellname: 'LUT4'


CRITICAL WARNING: [Constraints 18-617] Could not create 'LOCK_PINS' constraint because 'invalid pin pair 'ALL''. [/../sdramsubsystem.edf:752]

Solution

To overcome the above error message, instead of using "LOCK_PINS = ALL", use dedicated pin locking for XDC constraints.

For example:

set_property LOCK_PINS {I3:A1 I2:A5 I1:A4 I0:A3} [get_cells u_dqs_mux/dqs_p_delay_02]


Or using the Vivado GUI:
1) Open Synthesized design
2) Right click on LUT
3) Select LOCK Input Instance Pins
57068-1.JPG
57068-1.JPG



For Fixed-placement of LUT, use the below constraints:
 

set_property BEL C6LUT [get_cells u_dqs_mux/dqs_p_delay_02]
set_property LOC SLICE_X396Y251 [get_cells u_dqs_mux/dqs_p_delay_02]
set_property LOCK_PINS {I3:A1 I2:A5 I1:A4 I0:A3} [get_cells u_dqs_mux/dqs_p_delay_02]


For Fixed-placement of LUT using the Vivado GUI:
 
1) Open Synthesized design
2) Right click on LUT
3) Select LOCK Input Instance Pins.
57068-2.JPG

 
4) Go to attribute and check the IS_BEL_FIXED and IS_LOC_FIXED boxes.
57068_2.JPG



AR# 57068
Date Created 08/11/2013
Last Updated 03/23/2015
Status Active
Type General Article
Devices
  • Virtex-7
Tools
  • Vivado Design Suite - 2012.4