利用CASE语句的3-8译码器,3个为数据输入,3个为控制端,分别为S1,S2,S3,输出数据为八位-Use CASE statement 3-8 decoder, three for data entry, three for the control side, namely S1, S2, S3, output data for eight

mux 4x1 with 2 control inputs, written in VHDL using 3 mathods: Logic gates, if, case. the fastest model is the one implemented with the case code.

module song(clk,key,song_out,led) input [7:0] key input clk output song_out output [7:0] led reg song_reg reg [21:0] count reg [19:0] delay reg [7:0] key_reg always @(posedge clk) begin count=count+1 if((count==de