rec_code:
begin
ir_cnt<=ir_cnt+1'b1;
if(ir_negedge)     可以用ir_posedge替换吗？我认为是可以的，既然是以脉冲时间间隔来区分0和1
begin
rec_cnt<=rec_cnt+1'b1;
ir_cnt<=9'd0;
if(low)
data[rec_cnt] <= 1'b0;
else if(high)
data[rec_cnt] <= 1'b1;
else
ir_state<=idle;
if(rec_cnt==5'd31)
begin
ir_state<=idle;
key_code<=data[23:16];
end
end
else
ir_state<=rec_code;
end