always @(posedge clk or negedge rst_n) begin if(~rst_n) fil_cnt <= 2'd0; else if(clk_key !=clk_key_reg) fil_cnt <= fil_cnt + 2'd1; else fil_cnt <= fil_cnt; end always @(posedge clk or negedge rst_n) begin if(~rst_n) clk_key_reg <= 1'b0; else if(&fil_cnt) clk_key_reg <= clk_key; else clk_key_reg <= clk_key_reg; end |