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现在在做输出偏移约束感觉比较奇怪的问题就是在约束一组八位数据的输出时有几位的结果差异很大具体如下:
Paths for end point dout<2> (W20.PAD), 1 path -------------------------------------------------------------------------------- Slack (slowest paths): -3.279 ns (requirement - (clock arrival + clock path + data path + uncertainty)) Source: dout_2 (FF) Destination: dout<2> (PAD) Source Clock: clk_out_OBUF_BUFG rising at 0.000ns Requirement: 5.000ns Data Path Delay: 3.731ns (Levels of Logic = 1) Clock Path Delay: 4.523ns (Levels of Logic = 2) Clock Uncertainty: 0.025ns
Clock Uncertainty: 0.025ns ((TSJ^2 + TIJ^2)^1/2 + DJ) / 2 + PE Total System Jitter (TSJ): 0.050ns Total Input Jitter (TIJ): 0.000ns Discrete Jitter (DJ): 0.000ns Phase Error (PE): 0.000ns
Maximum Clock Path at Slow Process Corner: clk_in to dout_2
Location Delay type Delay(ns) Physical Resource Logical Resource(s) ------------------------------------------------- ------------------- W12.I Tiopi 1.037 clk_in
clk_in
IBUFG_u0
ProtoComp0.IMUX.14
BUFGMUX_X2Y9.I0 net (fanout=2) 0.987 clk_out_OBUF
BUFGMUX_X2Y9.O Tgi0o 0.209 clk_out_OBUF_BUFG
clk_out_OBUF_BUFG
OLOGIC_X27Y31.CLK0 net (fanout=96) 2.290 clk_out_OBUF_BUFG
------------------------------------------------- --------------------------- Total 4.523ns (1.246ns logic, 3.277ns route) (27.5% logic, 72.5% route)
Maximum Data Path at Slow Process Corner: dout_2 to dout<2>
Location Delay type Delay(ns) Physical Resource Logical Resource(s) ------------------------------------------------- ------------------- OLOGIC_X27Y31.OQ Tockq 1.080 dout_2
dout_2
W20.O net (fanout=1) 0.309 dout_2
W20.PAD Tioop 2.342 dout<2>
dout_2_OBUF
dout<2>
------------------------------------------------- --------------------------- Total 3.731ns (3.422ns logic, 0.309ns route) (91.7% logic, 8.3% route)
--------------------------------------------------------------------------------
Fastest Paths: TIMEGRP "dout" OFFSET = OUT 5 ns AFTER COMP "clk_in" REFERENCE_PIN BEL "clk_out" TIMEGRP dout_r "RISING"; --------------------------------------------------------------------------------
Paths for end point dout<1> (U22.PAD), 1 path -------------------------------------------------------------------------------- Delay (fastest paths): 3.003 ns (clock arrival + clock path + data path - uncertainty) Source: dout_1 (FF) Destination: dout<1> (PAD) Source Clock: clk_out_OBUF_BUFG rising at 0.000ns Data Path Delay: 1.564ns (Levels of Logic = 1) Clock Path Delay: 1.464ns (Levels of Logic = 2) Clock Uncertainty: 0.025ns
Clock Uncertainty: 0.025ns ((TSJ^2 + TIJ^2)^1/2 + DJ) / 2 + PE Total System Jitter (TSJ): 0.050ns Total Input Jitter (TIJ): 0.000ns Discrete Jitter (DJ): 0.000ns Phase Error (PE): 0.000ns
Minimum Clock Path at Fast Process Corner: clk_in to dout_1
Location Delay type Delay(ns) Physical Resource Logical Resource(s) ------------------------------------------------- ------------------- W12.I Tiopi 0.321 clk_in
clk_in
IBUFG_u0
ProtoComp0.IMUX.14
BUFGMUX_X2Y9.I0 net (fanout=2) 0.265 clk_out_OBUF
BUFGMUX_X2Y9.O Tgi0o 0.059 clk_out_OBUF_BUFG
clk_out_OBUF_BUFG
OLOGIC_X27Y40.CLK0 net (fanout=96) 0.819 clk_out_OBUF_BUFG
------------------------------------------------- --------------------------- Total 1.464ns (0.380ns logic, 1.084ns route) (26.0% logic, 74.0% route)
Minimum Data Path at Fast Process Corner: dout_1 to dout<1>
Location Delay type Delay(ns) Physical Resource Logical Resource(s) ------------------------------------------------- ------------------- OLOGIC_X27Y40.OQ Tockq 0.336 dout_1
dout_1
U22.O net (fanout=1) 0.190 dout_1
U22.PAD Tioop 1.038 dout<1>
dout_1_OBUF
dout<1>
------------------------------------------------- --------------------------- Total 1.564ns (1.374ns logic, 0.190ns route) (87.9% logic, 12.1% route)
就不明白为什么dout【1】和dout【2】的结果差异这么大?如何可以让这一组数据约束出来结果差不多呢? |
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