求助，关于SRAM设计中出现latch

goodsaint

求助，关于SRAM设计中出现latch [复制链接]

我设计了一个SRAM，可是结果出现了8个12bit的latch，不知道怎么消去，还望高手帮忙，在此先谢过了
！代码如下：
module SRAM(CLK, CS, AWE, A, D, AOE);
input CLK;
input CS;
input AWE;
input [2:0] A;
inout [11:0] D;
input AOE;

reg [11:0] MEM [7:0];


//Only CS is low and AWE is high,then read option is valid!
assign D = (((!CS) && AWE)==1)?MEM[A]:12'bz;
//Only AOE is low,then output data stored in the RAM to the inner FPGA modoule.
assign D = ((CLK && (!AOE))==1)?MEM[A]:12'bz;

always @(CS or AWE or A or D)
begin
  if((!CS) && (!AWE))//Only CS and AWE are low,then write option is
valid!
  begin
  MEM[A] = D;
  end
  else MEM[A] = MEM[A];
end
endmodule

有下面的warnings:
============================================================
*                   HDL Synthesis                     *
============================================================

Synthesizing Unit <SRAM>.
  Related source file is "SRAM.v".
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_7>.
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_6>.
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_5>.
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_4>.
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_3>.
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_2>.
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_1>.
WARNING:Xst:737 - Found 12-bit latch for signal <MEM_0>.
  Found 12-bit tristate buffer for signal <D>.
  Found 12-bit 8-to-1 multiplexer for signal <$n0000> created at line 44.
  Summary:
   inferred 12 Multiplexer(s).
   inferred 24 Tristate(s).
Unit <SRAM> synthesized.

============================================================
*                 Low Level Synthesis                   *
============================================================
Loading device for application Rf_Device from file '3s400.nph' in environment C:\Xilinx.
WARNING:Xst:2040 - Unit SRAM: 12 multi-source signals are replaced by logic (pull-up yes): N11, N13, N15, N17, N19, N21, N23, N25, N27, N5, N7, N9.