1. Digilent Spartan 3 Board Discussion D3.3
7-Segment Displays
Digilent Spartan 3 Board
Discussion D3.3

2. Spartan 3 Board

3. Spartan 3 Board

4. Turning on an LED Note: A zero turns on the LED

5. Spartan 3 Board

6. 7-Segment Decoder
a-g LOW to turn on segment

7. 7-Segment Display Truth table q a b c d e f g 0 1 1 1 1 1 1 0
seg7dec
q(3:0)
AtoG(6:0)
Truth table
q a b c d e f g
q a b c d e f g A b C d E F

8. 7-Segment Decoder library IEEE; use IEEE.std_logic_1164.all;
entity seg7dec is
port (q: in STD_LOGIC_VECTOR(3 downto 0);
AtoG: out STD_LOGIC_VECTOR(6 downto 0));
end seg7dec;
seg7dec
q(3:0)
AtoG(6:0)

9. architecture seg7dec_arch of seg7dec is
begin
process(q)
case q is
when "0000" => AtoG <= " ";
when "0001" => AtoG <= " ";
when "0010" => AtoG <= " ";
when "0011" => AtoG <= " ";
when "0100" => AtoG <= " ";
when "0101" => AtoG <= " ";
when "0110" => AtoG <= " ";
when "0111" => AtoG <= " ";
when "1000" => AtoG <= " ";
when "1001" => AtoG <= " ";
when "1010" => AtoG <= " ";
when "1011" => AtoG <= " ";
when "1100" => AtoG <= " ";
when "1101" => AtoG <= " ";
when "1110" => AtoG <= " ";
when others => AtoG <= " ";
end case;
end process;
end seg7dec_arch;

10. 7-Segment Display Behavior (Active LOW) VHDL seg7dec q(3:0) AtoG(6:0)
with q select
AtoG <= " " when "0001", --1
" " when "0010", --2
" " when "0011", --3
" " when "0100", --4
" " when "0101", --5
" " when "0110", --6
" " when "0111", --7
" " when "1000", --8
" " when "1001", --9
" " when "1010", --A
" " when "1011", --b
" " when "1100", --C
" " when "1101", --d
" " when "1110", --E
" " when "1111", --F
" " when others; --0
Behavior
(Active LOW)
AtoG
seg7dec
q(3:0)
AtoG(6:0)

11. .ucf file NET "AN<0>" LOC = "E13" ;
NET "AN<1>" LOC = "F14" ;
NET "AN<2>" LOC = "G14" ;
NET "AN<3>" LOC = "d14" ;
NET "AtoG<6>" LOC = "E14" ;
NET "AtoG<5>" LOC = "G13" ;
NET "AtoG<4>" LOC = "N15" ;
NET "AtoG<3>" LOC = "P15" ;
NET "AtoG<2>" LOC = "R16" ;
NET "AtoG<1>" LOC = "F13" ;
NET "AtoG<0>" LOC = "N16" ;
NET "dp" LOC = "P16" ;