ISE编译如下代码出现如下提示，请高手指点！

hbchf

部分代码如下：
module con12(Reset,fin,cout,fout);
input Reset,fin;
output cout,fout;
reg cout;
reg [3:0] fout;
always @(posedge fin)
if(!Reset && fout<12)
   begin
    fout = fout+1;
     if(fout==10)  cout=1;
     else          cout=0;
    end
else       
fout = 0;
endmodule

module count1(Fx,Rst,fx1out,fx2out,fx3out,fx4out);
input Fx,Rst;
output  fx1out,fx2out,fx3out,fx4out;
reg [3:0] fx1out,fx2out,fx3out,fx4out;
wire [3:0] c1out,c2out,c3out,c4out;

con12 C1(.fin(Fx),.cout(c1out),.fout(fx1out));           ---line 7
con12 C2(.fin(c1out),.cout(c2out),.fout(fx2out));        ---line 8
con12 C3(.fin(c2out),.cout(c3out),.fout(fx3out));        ---line 9
con12 C4(.fin(c3out),.cout(),.fout(fx4out));             ---line 10
endmodule

编译提示：
ERROR:HDLCompilers:246 - "count1.v" line 7 Reference to vector reg 'fx1out' is not a legal net lvalue
ERROR:HDLCompilers:102 - "count1.v" line 7 Connection to output port 'fout' must be a net lvalue
ERROR:HDLCompilers:246 - "count1.v" line 8 Reference to vector reg 'fx2out' is not a legal net lvalue
ERROR:HDLCompilers:102 - "count1.v" line 8 Connection to output port 'fout' must be a net lvalue
ERROR:HDLCompilers:246 - "count1.v" line 9 Reference to vector reg 'fx3out' is not a legal net lvalue
ERROR:HDLCompilers:102 - "count1.v" line 9 Connection to output port 'fout' must be a net lvalue
ERROR:HDLCompilers:246 - "count1.v" line 10 Reference to vector reg 'fx4out' is not a legal net lvalue
ERROR:HDLCompilers:102 - "count1.v" line 10 Connection to output port 'fout' must be a net lvalue
-->
请高手指点下小弟！
谢谢了！

ngzhang

发现了至少一个问题。

reg [3:0] fx1out,fx2out,fx3out,fx4out;

这一句不能是reg。模块互联要用wire型变量。

edwin

con12  模块例化的时候没有指明reset的状态，应该不行吧
      c4out 怎么不写到最后一个con12里面去？
  没有仔细看明白代码