module pfd(Ref,div,dn,up,Din);
input Ref,div,Din;
output up,dn;
reg dn;
reg up;
reg rst;
always @(posedge Ref or posedge rst)
begin
if (rst==1)
dn<=0;
else
dn<=Din;
end
always @(posedge div or posedge rst)
begin
if (rst==1)
up<=0;
else
up<=Din;
end
always@(up[/email] or dn)
rst=up&dn;
endmodule
这个是程序
谢谢指教