关于ISE布线约束问题请教大神。

tobias

Place:866 - Not enough valid sites to place the following IOBs:
   IO Standard: Name = LVCMOS25, VREF = NR, VCCO = 2.50, TERM = NONE, DIR =
   BIDIR, DRIVE_STR = NR
2 C/ O& S# L9 _           IO_x_x_x_x_x_x_x
           IO_x_x_x_x_x_x
  ^0 z* s. Z, B' [           IO_x_x_x_x_x
0 ?$ Q5 R9 A6 w2 `2 q           IO_x_x_x_x
           IO_x_x_x
' X, x6 ?" r' R4 ?3 a' S           IO_x_x
           IO_x
           IO
! Q, U- o2 K* e2 j4 y
1 {) M+ R$ s; t   This may be due to either an insufficient number of sites available on the
   device, too many prohibited sites,
   or incompatible I/O Standards locked or range constrained to I/O Banks with
8 K! e6 K; R( u" \4 \7 C' J3 ~# {$ @   valid sites.
       This situation could possibly be resolved by one (or all) of the
1 c6 f8 W2 K( i2 t   following actions:
   a) Grouping IOBs of similar standards into a minimum amount of I/O Banks by
0 {+ v+ }# x. l( b8 H- S   using LOC or range constraints.
   b) Maximizing available I/O Banks resources for special IOBs by choosing
$ Z4 q; i1 ~' Z8 [2 P   lower capacity I/O Banks if possible.
   c) If applicable, decreasing the number of user prohibited sites or using a
   larger device.
* N' x7 f" p2 e4 z1 {5 y+ l我UCF里根本没有用到LVCMOS25。warnings里也没什么异常啊。
: _5 E; |' ?  u$ E" b0 a请教大神，非常感谢！
5 M; J3 a- d  f

Demyar

路过帮顶。