1. Digilent Spartan 3 Board Lecture L2.2
7-Segment Displays
Digilent Spartan 3 Board
Lecture L2.2

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. Multiplex displays

8. Multiplex displays 1 1 1

9. Multiplex displays 1 1 1

10. Multiplex displays 1 1 1

11. Multiplex displays 1 1 1

12. x7seg

13. x7seg.vhd library IEEE; use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity x7seg is
Port ( x : in std_logic_vector(15 downto 0);
cclk, clr : in std_logic;
AtoG : out std_logic_vector(6 downto 0);
A : out std_logic_vector(3 downto 0) );
end x7seg;

14. architecture arch_x7seg of x7seg is
signal digit : std_logic_vector(3 downto 0);
signal count : std_logic_vector(1 downto 0);
begin

15. ctr2bit: process(cclk,clr)
begin
if(clr = '1') then
count <= "00";
elsif(cclk'event and cclk = '1') then
count <= count + 1;
end if;
end process;

16. -- MUX4
with count select
digit <= x(3 downto 0) when "00",
x(7 downto 4) when "01",
x(11 downto 8) when "10",
x(15 downto 12) when others;

17. -- seg7dec
with digit 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

18. Example: count = 10 AN(2) = 0 AN(0) = AN(1) = AN(3) = 1 AN(3:0) = 1011
ANcode: process(count)
begin
A <= (others => '1');
A(conv_integer(count)) <= '0';
end process;
end arch_x7seg;
Example:
count = 10
AN(2) = 0
AN(0) = AN(1) = AN(3) = 1
AN(3:0) = 1011

19. .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" ;