我用define定义了两个数,系统一直报错,未定义
`timescale 1ns/1ps
`define SS 32'd49999999
`define DD 32'd50000000
module LED
(
clk,
rst_n,
led
);
input clk;
input rst_n;
output[3:0] led;
reg[31:0] timer;
reg[3:0] led;
always@(posedge clk or negedge rst_n)
begin
if(~rst_n)
timer<=0;
else if(timer == SS+5*DD)
timer<=0;
else
timer<=timer+1'b1;
end
always@(posedge clk or negedge rst_n)
begin
if(~rst_n)
led<=4'b1111;
else if(timer==SS)
led<=4'b1110;
else if((timer==SS+DD)|(timer==SS+5*DD))
led<=4'b1101;
else if((timer==SS+2*DD)|(timer==SS+4*DD))
led<=4'b1011;
else if(timer==SS+3*DD)
led<=4'b0111;
end
endmodule
我把define这两句放到module中间定义也不对,这是因为啥原因?