Spartan IODELAY2计算的最大延迟如何预测

敬启者！
在“Spartan-6 FPGA数据手册：DC amd开关特性”之后，IODELAY2元件Spartan6的最大延迟定义为：
最大延迟=整数（抽头数/ 8）X Ttap8 + Ttapn。
因此，如果速度等级为3的Spartan6具有下一个最大延迟时间：
Ttap1 = 8 ps
Ttap2 = 40 ps
Ttap3 = 95 ps
Ttap4 = 108 ps
Ttap5 = 171 ps
Ttap6 = 207 ps
Ttap7 = 212 ps
Ttap8 = 292 ps
如果IODELAY2元素有参数IDELAY_VALUE = 2那么我正在等待IODELAY2的最大延迟：
整数（2/8）X Ttap8 + Ttap2 = 0 X Ttap8 + Ttap2 = 0 X 292 ps + 40 ps = 40 ps。
但是在P'n'R跟踪后给我的值为tioddo_IDATAIN = 2.128 ns，
Coregen计算延迟为2.925 ns，
ISIM在行为模拟中显示延迟约130 ps
老实说我对这种结果的分散感到困惑，
我的问题是：“有人知道如何预测/计算这种延迟”
第二个问题是：
“有人知道SIM_TAPDELAY_VALUE参数是什么意思（但请不要引用数据表中的参数描述 - 我读过这个但我现在还不清楚）”
先谢谢你
Motspan Viktor



以下为原文

Dear Sirs!
Following "Spartan-6 FPGA Data Sheet: DC amd switching Characteristics" the maximum delay of IODELAY2 element Spartan6 is defined as:
Maximum delay = integer(number of taps/8) X Ttap8 + Ttapn.
So, if Spartan6 with speed grade -3 have the next maximum delays for taps:
Ttap1 = 8 ps
Ttap2 = 40 ps
Ttap3 = 95 ps
Ttap4 = 108 ps
Ttap5 = 171 ps
Ttap6 = 207 ps
Ttap7 = 212 ps
Ttap8 = 292 ps

and if IODELAY2 element have parameter IDELAY_VALUE=2 then I am awaiting maximum delay of IODELAY2 as:
integer(2/8) X Ttap8 + Ttap2 = 0 X Ttap8 + Ttap2 = 0 X 292 ps + 40 ps = 40 ps.

But after P'n'R trace give me value of  Tioddo_IDATAIN = 2.128 ns,
Coregen calculate delay as 2.925 ns,
ISIM shows in behavioral simulation delay about 130 ps

Honestly say I am really confused by such dispersion in results,
and my question is: "Does someone know how to predict/calculate this delay"

And second question is:
"Does someone know what does SIM_TAPDELAY_VALUE parameter mean (but please do not quote parameter description from datasheet - I read this but it is still not clear for me)"


Thank you in advance
Motspan Viktor