1. Decoders and Encoders
Sections 3-5, 3-6 Mano & Kime

2. Decoders and Encoders Binary Decoders Binary Encoders
Priority Encoders

3. Decoders

5. 3-to-8 Line Decoder

6. A 2-to-4-Line Decoder

7. Implementing a Binary Adder Using a Decoder
S(X,Y,Z) = Sm(1,2,4,7)
C(X,Y,Z) = Sm(3,5,6,7)

8. Decoder Networks

9. 4-input tree decoder

11. Decoder uses

12. Decoder uses

14. Decoders and Encoders Binary Decoders Binary Encoders
Priority Encoders

15. Binary encoders

16. A0 = D1 + D3 + D5 + D7
A1 = D2 + D3 + D6 + D7
A2 = D4 + D5 + D6 + D7

18. Uses of binary encoders

19. Decoders and Encoders Binary Decoders Binary Encoders
Priority Encoders

21. Maps of Priority Encoder

22. Logic Diagram of a 4-Input Priority Encoder

23. Uses of priority encoders

24. VHDL Example: 8-input priority encoder

25. entity pencoder is
port (
x: in STD_LOGIC_VECTOR (7 downto 0);
E: in STD_LOGIC;
y: out STD_LOGIC_VECTOR (2 downto 0);
A: out STD_LOGIC );
end pencoder;

26. architecture pencoder_arch of pencoder is
begin
pe: process(x,E)
variable k: integer;
y <= "000";
A <= '0';
if E = '1' then
for j in 0 to 7 loop
if x(j) = '1' then
y <= conv_std_logic_vector(j,3);
A <= '1';
end if;
end loop;
end process pe;
end pencoder_arch;