VHDL: 四合一七段顯示器解碼器

         這個練習用VHDL設計一個四合一的七段顯示器解碼器，然後燒錄電路於CPLD中，再用Arduino與其對接，用程式驗證此解碼器的正確性。


          用VHDL語法撰寫的四合一的七段顯示器解碼器原始碼:

ibrary ieee;
use ieee.std_logic_1164.all;

entity seven_seg_4in1 is 
port(    com_in:     in  std_logic_vector(1 downto 0);
            num_in:    in  std_logic_vector(3 downto 0);
          com_out: out  std_logic_vector(3 downto 0);
           num_out: out  std_logic_vector(7 downto 0)
           );
 end seven_seg_4in1;

 architecture x of  seven_seg_4in1 is
 begin
 with com_in select 
com_out <= "0001" when "00",
                    "0010" when "01",
                    "0100" when "10",
                    "1000" when "11",
                    "0000" when others;
 
with num_in select
num_out<="11000000" when "0000",
"11111001" when "0001",
"10100100" when "0010",
"10110000" when "0011",
"10011001" when "0100",
"10010010" when "0101",
"10000010" when "0110",
"11111000" when "0111",
"10000000" when "1000",
"10011000" when "1001",
"10001000" when "1010",
"10000011" when "1011",
"11000110" when "1100",
"10100001" when "1101",
"10000110" when "1110",
"10001110" when "1111";
 end x;

腳位配置圖(Pin Asignment)

Arduino 端的程式碼:

#define com_in_0 4
#define com_in_1 5
#define num_in_0 8 
#define num_in_1 9
#define num_in_2 10
#define num_in_3 11

void setup() {
  pinMode(com_in_0, OUTPUT);
  pinMode(com_in_1, OUTPUT);
  pinMode(num_in_0, OUTPUT);
  pinMode(num_in_1, OUTPUT);
  pinMode(num_in_2, OUTPUT);
  pinMode(num_in_3, OUTPUT);
  
}

void loop() {
 int i, j;
 for(j=0; j<4; j++)
 {
    digitalWrite(com_in_1, (j>>1)&1); 
    digitalWrite(com_in_0, j&1); 
    
    for(i=0; i<16; i++)
    {
      digitalWrite(num_in_3, (i>>3)&1); 
      digitalWrite(num_in_2, (i>>2)&1); 
      digitalWrite(num_in_1, (i>>1)&1); 
      digitalWrite(num_in_0, i&1);
      delay(300);
    }
 }
}

執行結果: