关于modelsim-altera的仿真问题
时间:10-02
整理:3721RD
点击:
这是5分频verilog文件:
module div_5(
input in_clk,
input in_rst_n,
output out_clk);
reg[2:0] cnta;
reg[2:0] cntb;
reg clka;
reg clkb;
always @(posedge in_clk ,negedge in_rst_n)
begin
if(!in_rst_n)
cnta<=0;
else if(cnta==4)
cnta<=0;
else
cnta<=cnta+1;
end
always @(posedge in_clk , negedge in_rst_n)
begin
if(!in_rst_n)
clka<=0;
else if(cnta<2)
clka<=1;
else
clka<=0;
end
always @(negedge in_rst_n , negedge in_clk)
begin
if(!in_rst_n)
cntb<=0;
else if (cntb==4)
cntb<=0;
else
cntb<=cntb+1;
end
always @(negedge in_clk , negedge in_rst_n)
begin
if(!in_rst_n)
clkb<=0;
else if(cntb<2)
clkb<=1;
else
clkb<=0;
end
assign out_clk=clka|clkb;
endmodule
我用quartus ii自带的波形仿真能看仿真结果。但是用modelsim-altera就没有输出波形
下面是testbench
`timescale 1 ns/ 1 ns
module div_5_vlg_tst();
reg in_clk;
reg in_rst_n;
wire out_clk;
div_5 i1 (
.in_clk(in_clk),
.in_rst_n(in_rst_n),
.out_clk(out_clk)
);
initial
begin
in_clk=1;
in_rst_n=1;
end
always #10 in_clk=~in_clk;
endmodule
提示有:
# ** Warning: (vsim-3009) [TSCALE] - Module 'div_5' does not have a `timescale directive in effect, but previous modules do.
module div_5(
input in_clk,
input in_rst_n,
output out_clk);
reg[2:0] cnta;
reg[2:0] cntb;
reg clka;
reg clkb;
always @(posedge in_clk ,negedge in_rst_n)
begin
if(!in_rst_n)
cnta<=0;
else if(cnta==4)
cnta<=0;
else
cnta<=cnta+1;
end
always @(posedge in_clk , negedge in_rst_n)
begin
if(!in_rst_n)
clka<=0;
else if(cnta<2)
clka<=1;
else
clka<=0;
end
always @(negedge in_rst_n , negedge in_clk)
begin
if(!in_rst_n)
cntb<=0;
else if (cntb==4)
cntb<=0;
else
cntb<=cntb+1;
end
always @(negedge in_clk , negedge in_rst_n)
begin
if(!in_rst_n)
clkb<=0;
else if(cntb<2)
clkb<=1;
else
clkb<=0;
end
assign out_clk=clka|clkb;
endmodule
我用quartus ii自带的波形仿真能看仿真结果。但是用modelsim-altera就没有输出波形
下面是testbench
`timescale 1 ns/ 1 ns
module div_5_vlg_tst();
reg in_clk;
reg in_rst_n;
wire out_clk;
div_5 i1 (
.in_clk(in_clk),
.in_rst_n(in_rst_n),
.out_clk(out_clk)
);
initial
begin
in_clk=1;
in_rst_n=1;
end
always #10 in_clk=~in_clk;
endmodule
提示有:
# ** Warning: (vsim-3009) [TSCALE] - Module 'div_5' does not have a `timescale directive in effect, but previous modules do.
你的5分频程序有问题
学习了
看不出有什么错误,请指点。
