我写了个跟踪输入波形的程序，仿真是正确的，但下载到板子上老是执行一段时间输出就拉高了，怎么回事？
case current_state is
when s0 =>
if cs='0' then
temp:=0;
current_state<=next_state;
csbuf<='0';
end if;
when s1 =>
if cs='1' then
current_state<=next_state;
csbuf<='1';
end if;
when s2=>
-- if temp/=n then
-- temp:=temp+1;
-- else
-- temp:=0;
current_state<=next_state;
-- end if;
when s3 =>
-- csout<='0';
current_state<=next_state;
end case;
csout<=csbuf;
