我的任务是编写一个简单的2-4解码器,然后显示可能的结果和波形。
我使用gEDA套件和Icarus Verilog (iVerilog)作为编译器,GTKWave作为波形。
这是我第一次用Verilog编码或使用gEDA套件。从google上看,我需要遵循这个designflow。
testbench文件无法编译,我不知道为什么,我试了好几种变化,但一直出现错误。任何帮助都是非常感激的。谢谢你的帮助。
这是我的设计文件代码。
// 2 to 4 Decoder
// File Name: decoder.v
module decoder(X,Y,E,Z);
input X,Y,E;
output [0:3]Z;
wire [0:3]Z;
wire X1, Y1;
not
inv1(X1,X),
inv2(Y1,Y);
and
and1(Z[0],X1,Y1,E),
and2(Z[1],Y1,X,E),
and3(Z[2],Y,X1,E),
and4(Z[3],X,Y,E);
endmodule
这是我的测试平台代码
module decoder_tb;
input X,Y,E;
output [0:3]Z;
//wire [0:3]Z;
//wire X1, Y1;
// should create .vcd dump file for GTKWave
initial
begin
$dumpfile("decoder.vcd");
$dumpvars();
end
decoder decode(X,Y,E,Z);
initial
begin
$display($time,"<< Z[0]=%d Z[1]=%d Z[2]=%d Z[3]=%d >>", Z[0] , Z[1] , Z[2] , Z[3] );
end
initial
begin
#0
X = 0; Y = 0; E = 1;
#5
X = 0; Y = 1; E = 1;
#10
X = 1; Y = 0; E = 1;
#15
X = 1; Y = 1; E = 1;
end
endmodule
我在终端使用的命令是:
iverilog -o decoder.vvp decoder.v decoder_tb.v
gtkwave decoder.vcd
编辑:这是准确的错误信息
aj@aj:~/verilogCode$ iverilog -o decoder.vvp decoder.v decoder_tb.v
decoder_tb.v:26: error: X is not a valid l-value in decoder_tb.
decoder_tb.v:6: : X is declared here as wire.
decoder_tb.v:26: error: Y is not a valid l-value in decoder_tb.
decoder_tb.v:6: : Y is declared here as wire.
decoder_tb.v:26: error: E is not a valid l-value in decoder_tb.
decoder_tb.v:6: : E is declared here as wire.
decoder_tb.v:28: error: X is not a valid l-value in decoder_tb.
decoder_tb.v:6: : X is declared here as wire.
decoder_tb.v:28: error: Y is not a valid l-value in decoder_tb.
decoder_tb.v:6: : Y is declared here as wire.
decoder_tb.v:28: error: E is not a valid l-value in decoder_tb.
decoder_tb.v:6: : E is declared here as wire.
decoder_tb.v:30: error: X is not a valid l-value in decoder_tb.
decoder_tb.v:6: : X is declared here as wire.
decoder_tb.v:30: error: Y is not a valid l-value in decoder_tb.
decoder_tb.v:6: : Y is declared here as wire.
decoder_tb.v:30: error: E is not a valid l-value in decoder_tb.
decoder_tb.v:6: : E is declared here as wire.
decoder_tb.v:32: error: X is not a valid l-value in decoder_tb.
decoder_tb.v:6: : X is declared here as wire.
decoder_tb.v:32: error: Y is not a valid l-value in decoder_tb.
decoder_tb.v:6: : Y is declared here as wire.
decoder_tb.v:32: error: E is not a valid l-value in decoder_tb.
decoder_tb.v:6: : E is declared here as wire.
12 error(s) during elaboration.
在你的测试平台中,将 input
到 reg
和 output
到 wire
. 这为我解决了编译错误(尽管我没有使用gEDA或iVerilog)。
module decoder_tb;
reg X,Y,E;
wire [0:3]Z;
在这种情况下,我的仿真器给出的错误信息比你的更有意义。
标识符 'X' 没有出现在 port 列表中。