CONSTRAINTS

Sir When we run our vhdl programme it sysnthesize and implemented witout any error, In place and route report it gives as:

Generating Clock Report

**************************

+---------------------+--------------+------+------+------------+-------------+ | Clock Net | Resource |Locked|Fanout|Net Skew(ns)|Max Delay(ns)|

+---------------------+--------------+------+------+------------+-------------+ | clk_BUFGP | BUFGMUX0P| No | 1886 | 0.280 | 1.257 |

+---------------------+--------------+------+------+------------+-------------+ | s_clk | BUFGMUX5S| No | 174 | 0.205 | 1.238 |

+---------------------+--------------+------+------+------------+-------------+ | hyperdis/h_clk | BUFGMUX2P| No | 38 | 0.273 | 1.250 |

+---------------------+--------------+------+------+------------+-------------+ | s_clk1 | Local| | 62 | 0.213 | 2.535 |

+---------------------+--------------+------+------+------------+-------------+ | trpcnt_cmp_eq0000 | Local| | 18 | 0.000 | 1.360 |

+---------------------+--------------+------+------+------------+-------------+

• Net Skew is the difference between the minimum and maximum routing only delays for the net. Note this is different from Clock Skew which is reported in TRCE timing report. Clock Skew is the difference between the minimum and maximum path delays which includes logic delays.

Timing Score: 232989

INFO:Timing:2761 - N/A entries in the Constraints list may indicate that the constraint does not cover any paths or that it has no

requested value. Asterisk (*) preceding a constraint indicates it was not met. This may be due to a setup or hold violation.

------------------------------------------------------------------------------------------------------ Constraint | Check | Worst Case | Best Case | Timing | Timing

| | Slack | Achievable | Errors | Score

------------------------------------------------------------------------------------------------------ Autotimespec constraint for clock net clk | SETUP | N/A|

45.997ns| N/A| 0

_BUFGP | HOLD | 0.543ns| | 0| 0

------------------------------------------------------------------------------------------------------ Autotimespec constraint for clock net hyp | SETUP | N/A|

20.484ns| N/A| 0

erdis/h_clk | HOLD | 0.658ns| | 0| 0

------------------------------------------------------------------------------------------------------

• Autotimespec constraint for clock net s_c | SETUP | N/A|

11.313ns| N/A| 0

lk1 | HOLD | -2.837ns| | 124| 232989

------------------------------------------------------------------------------------------------------

1 constraint not met. INFO:Timing:2761 - N/A entries in the Constraints list may indicate that the

constraint does not cover any paths or that it has no requested value.

Generating Pad Report.

All signals are completely routed. Sir I want to know what's meaning of 1 constraint not met and how I resolve it.

Thanks Varun

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