AR# 15804


8.1i Virtex-II MAP - "ERROR:LIT - PSINCDEC, PSEN, PSCLK and PSDONE of DCM symbol... must be connected..."


When I run MAP, the following error occurs: 


"ERROR:LIT - PSINCDEC, PSEN, PSCLK, and PSDONE of DCM symbol <> with output signal <> must be connected to GND when clkout_phase_shift is set to 'none' or 'fixed'."


In "Fixed" and/or "None" mode, the PSINCDEC, PSEN, PASCAL, and PS DONE pins of the DCM symbol have no use, and must therefore be grounded. However, in variable mode, the phase factor can be changed by activating PSEN for one period of PSCLK. You can make increments or decrements to the phase factor by setting the PSINCDEC pin to a High or Low, respectively.  


When the de-skew circuit has completed an increment or decrement operation, the signal PSDONE goes High for a single PSCLK cycle. This indicates that the next change can be made. 


Setting the clkout_phase_shift attribute to "Variable" will solve this problem. 


More constraints information for the clkout_phase_shift is available at:

The Virtex-II Data Sheet (DCM) is available at:

AR# 15804
Date 05/15/2014
Status Archive
Type General Article
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