映射错误866：没有足够的有效站点来放置以下IOB

我正在使用带有Spartan-6 150T FG484的ISE 14.2嵌入式版本。
我的设计包含一个MicroBlaze处理器。
我从SP605板开始使用原型设计，并使用更大的设备转换为我的真实设计。
我小心更新所有设备引用以使用更大的150T设备。
SP605使用LVCMOS25，而我的电路板使用LVCMOS33。
我用我的所有信号填写了我的UCF文件，但只有一些导致了错误。
这是我从Map获得的错误：
信息：位置：834  - 仅锁定IO的子集。
在92个IO中，89个被锁定，3个未被锁定。
以下是未锁定的组件列表。
OA_o_SYS_OK未锁定OA_o_HP_INHIBIT未锁定OA_o_ATTENUAtiON_EN未锁定其余IO已锁定错误：放置：866  - 没有足够的有效站点放置以下IOB：IO标准：名称= LVCMOS25，VREF = NR，VCCO = 2.50，TERM = NONE，
DIR = OUTPUT，DRIVE_STR = 12 OA_o_SYS_OK OA_o_HP_INHIBIT OA_o_ATTENUATION_EN这可能是由于设备上可用站点数量不足，禁止站点过多，或者I / O标准不兼容，或者范围受限于具有有效站点的I / O Bank。
这种情况可以通过以下一个（或全部）动作来解决：a）通过使用LOC或范围约束将类似标准的IOB分组到最小量的I / O Bank中。
b）如果可能，通过选择较低容量的I / O Bank，为特殊IOB最大化可用的I / O Bank资源。
c）如果适用，减少用户禁止站点的数量或使用更大的设备。
以下是我的UCF文件中的相应条目：
NET OA_o_SYS_OK LOC =“B20”|
IOSTANDARD =“LVCMOS33”;
NET OA_o_HP_INHIBIT LOC =“F22”|
IOSTANDARD =“LVCMOS33”; NET OA_o_ATTENUATION_EN LOC =“J20”|
IOSTANDARD =“LVCMOS33”;
你可以看到我确实有这些LOCKED。
在我的MHS文件中：
端点OA_o_ATTENUATION_EN = OA_o_ATTENUATION_EN，DIR = OPORT OA_o_HP_INHIBIT = OA_o_HP_INHIBIT，DIR = OPORT OA_o_SYS_OK = OA_o_SYS_OK，DIR = O，SIGIS = NONE
我已经尝试将SYS_OK的IO引脚从B20交换到A20，其中A20位于不会出错的引脚上，但它仍然说SYS_OK没有锁定并给出完全相同的错误。
我甚至尝试删除SYS_OK，它名为OK，并用新名称SYS_OK添加回来，但我仍然得到同样的错误。
我还清理了设计文件并重新设计了干净的设计。
没有运气。
我从阅读中知道LVCMOS25是默认的，因此如果引脚被锁定，为什么它们会转到LVCMOS25。
我不明白的是为什么他们没有锁定。
知道这里发生了什么吗？
谢谢。



以下为原文

I am using ISE 14.2 Embedded Edition with a Spartan-6 150T FG484.

My design contains a single MicroBlaze processor.

I started with a prototype design from an SP605 board and converted to my real design using the larger device.  I was careful to update all device references to use the larger 150T device.

The SP605 uses LVCMOS25 whereas my board with use LVCMOS33.

I filled in my UCF file with all my signals, but only some caused errors.

Here is the error I get from Map:
INFO:Place:834 - Only a subset of IOs are locked. Out of 92 IOs, 89 are locked
   and 3 are not locked.  The following is the list of components that are not
   locked.
   OA_o_SYS_OK      NOT LOCKED
   OA_o_HP_INHIBIT      NOT LOCKED
   OA_o_ATTENUATION_EN      NOT LOCKED
   Rest of the IOs are LOCKED

ERROR:Place:866 - Not enough valid sites to place the following IOBs:
   IO Standard: Name = LVCMOS25, VREF = NR, VCCO = 2.50, TERM = NONE, DIR =
   OUTPUT, DRIVE_STR = 12
       OA_o_SYS_OK
       OA_o_HP_INHIBIT
       OA_o_ATTENUATION_EN

   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
   valid sites.
       This situation could possibly be resolved by one (or all) of the
   following actions:
   a) Grouping IOBs of similar standards into a minimum amount of I/O Banks by
   using LOC or range constraints.
   b) Maximizing available I/O Banks resources for special IOBs by choosing
   lower capacity I/O Banks if possible.
   c) If applicable, decreasing the number of user prohibited sites or using a
   larger device.


And here are the corresponding entries in my UCF file:
NET OA_o_SYS_OK LOC = "B20" | IOSTANDARD = "LVCMOS33";

NET OA_o_HP_INHIBIT LOC = "F22" | IOSTANDARD = "LVCMOS33";

NET OA_o_ATTENUATION_EN LOC = "J20" | IOSTANDARD = "LVCMOS33";


You can see that I do in fact have these LOCKED.  

And in my MHS file:
PORT OA_o_ATTENUATION_EN = OA_o_ATTENUATION_EN, DIR = O
PORT OA_o_HP_INHIBIT = OA_o_HP_INHIBIT, DIR = O
PORT OA_o_SYS_OK = OA_o_SYS_OK, DIR = O, SIGIS = NONE


I have tried swapping IO pins for SYS_OK from B20 to A20 where A20 is on a pin that does not give errors, but it still says SYS_OK is not LOCKED and gives the exact same error.

I even tried removing SYS_OK which was orginally name OK and adding it back in with a new name SYS_OK and still I have get the same error.

I have also cleaned design files and rebuilt the design clean.  No luck.

I know from reading around that LVCMOS25 is the default so that makes sense as to why if the pins are LOCKED they go to LVCMOS25.  What I don't understand is why are they not LOCKED.

Any idea what is going on here?

Thanks.