CPLD-VHDL 國立新營高工 WWW.HYIVS.TNC.EDU.TW 沈慶陽

VHDL範例 真值表 LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY true IS Port (a,b,c:in STD_Logic; y:out STD_Logic); End true; ARCHITECTURE a OF true IS Begin Y<=((not a) and b and (not c)) or (a and b and (not c)); End a;

VHDL範例 解碼器(2對4) LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY decoder2_4 IS Port (s1,s0:in STD_Logic; m0,m1,m2,m3:out STD_Logic); End decoder2_4; ARCHITECTURE a OF decoder2_4 IS Begin m0<=(not s0) and (not s1); m1<= s0 and (not s1); m2<= (not s0) and s1; m3<= s0 and s1; End a;

VHDL範例 4對1多工器 LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY mux4_1 IS Port(s1,s0,d0,d1,d2,d3:in STD_Logic; Y:out STD_Logic); End mux4_1; ARCHITECTURE a OF mux4_1 IS Begin Y<=((not s0) and (not s1) and d0) or (s0 and (not s1) and d1) or ((not s0) and s1 and d2) or (s0 and s1 and d3); End a;

VHDL範例 1對4解多工器 LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY demux1_4 IS Port(d,s1,s0:in STD_Logic; d0,d1,d2,d3:out STD_Logic); End demux1_4; ARCHITECTURE a OF demux1_4 IS Begin d0<= d and (not s0) and (not s1); d1<= d and s0 and (not s1); d2<= d and (not s0) and s1; D3<= d and s0 and s1; End a;

VHDL行為性描述—並行敘述式指令 條件式的訊號設定敘述:When – Else 訊號Y<=訊號A When (條件1) Else 訊號B When (條件2) Else 訊號C; 選擇式的訊號設定敘述:With – Select – When With 選擇訊號 X Select 訊號Y<=訊號A When 選擇訊號X 為m, 訊號B When 選擇訊號X 為n, : 訊號Z When Others;

範例:真值表使用並行敘述When-Else LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY true_table IS Port (x:in STD_Logic_Vector(2 downto 0); y:out STD_Logic); End true_table; ARCHITECTURE a OF true_table IS Begin Y<= ‘1’ When x=“010” Else ‘1’ when x=“110” Else ‘0’; End a;

VHDL範例 解碼器(2對4)When-Else LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY decoder2_4w IS Port (s:in Std_Logic_Vector(1 downto 0); m0,m1,m2,m3:out Std_Logic); End decoder2_4w; ARCHITECTURE a OF decoder2_4w IS Begin m0<=‘1’ when s=“00” Else ‘0’; m1<=‘1’ when s=“01” Else ‘0’; m2<= ‘1’ when s=“10” Else ‘0’; m3<= ‘1’ when s=“11”Else ‘0’; End a;

範例 具有EN的解碼器(2對4)When-Else LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY decoder2_4w IS Port (s:in Std_Logic_Vector(1 downto 0); en:in std_logic; y:out Std_Logic_vector(3 downto 0)); End decoder2_4w; ARCHITECTURE a OF decoder2_4w IS Begin y<="1000" when en= '1' and s="00" else "0100" when en= '1' and s="01" else "0010" when en= '1' and s="10" else "0001" when en= '1' and s="11" else "0000" ; End a;

VHDL範例 4對1多工器When-Else LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY mux4_1w IS Port (s:in Std_Logic_Vector(1 downto 0); d0,d1,d2,d3:in STD_Logic; Y:out STD_Logic); End mux4_1w; ARCHITECTURE a OF mux4_1w IS Begin Y<= d0 When s=“00” Else d1 When s=“01” Else d2 When s=“10” Else d3; End a;

VHDL範例 優先權電路When-Else LIBRARY IEEE; use IEEE.STD_Logic_1164.all; ENTITY priority is port (d0,d1,d2,d3:in std_logic; y:out std_logic_vector(1 downto 0)); end priority; ARCHITECTURE a of priority IS BEGIN y <= "11" when (d3='1)' else--高優先-- "10" when (d2='1‘) else "01" when (d1='1‘) else "00" ; --low priority END a;

VHDL範例 優先權電路When-Else LIBRARY IEEE; use IEEE.STD_Logic_1164.all; ENTITY priority is port (d:in std_logic_vector(3 downto 0); y:out std_logic_vector(1 downto 0)); end priority; ARCHITECTURE a of priority IS BEGIN y <= "11" when d(3)='1' else--高優先-- "10" when d(2)='1' else "01" when d(1)='1' else "00" ; --low priority END a;

範例:真值表並行敘述With-Select-When LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY true_table IS Port (x:in STD_Logic_Vector(2 downto 0); y:out STD_Logic); End true_table; ARCHITECTURE a OF true_table IS Begin With x Select Y<= ‘1’ When “010”, ‘1’ When “110”, ‘0’ When Others; End a;

VHDL範例 解碼器(2對4)With-Select-When LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY decoder2_4ws IS Port (s:in Std_Logic_Vector(1 downto 0); m:out Std_Logic_Vector(3 downto 0)); End decoder2_4ws; ARCHITECTURE a OF decoder2_4ws IS Begin With s Select m<=“0001” when “00” , “0010” when “01” , “0100” when “10”, “1000” when “11”, “0000” when others; End a; 嘗試依此例作 3對8及4對16 之解碼器

VHDL範例 編碼器(4對2)With-Select-When LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY encoder4_2 IS Port (d:in Std_Logic_Vector(3 downto 0); y:out Std_Logic_Vector(1 downto 0)); End encoder4_2; ARCHITECTURE a OF encoder4_2 IS Begin With d Select y<=“00” when “0001” , “01” when “0010” , “10” when “0100”, “11” when “1000”, “00” when others; End a; 嘗試依此例作 8對3及16對4 之編碼器

VHDL範例 七段顯示器解碼電路With-Select-When y:out Std_Logic_Vector(6 downto 0)); End sev_seg; ARCHITECTURE a OF sev_seg IS Begin With d Select y<=“1111110” when “0000” , “0110000” when “0001” , “1101101” when “0011”, “1111001” when “0011”, “0110011” when “0100”, “1011011” when “0101”, “1011111” when “0110”, “1110000” when “0111”, “1111111” when “1000”, “1111011” when “1001”, “1110111” when “1010”, “0011111” when “1011”, “1001110” when “1100”, “0111101” when “1101”, “1001111” when “1110”, “1000111” when “1111”, “0000000” when others; End a; LIBRARY IEEE; USE IEEE.STD_LOGIC_1164.all; ENTITY sev_seg IS Port (d:in Std_Logic_Vector(3 downto 0);

範例:簡易ALU設計With-Select-When LIBRARY IEEE; use IEEE.STD_Logic_1164.all; use IEEE.STD_Logic_unsigned.all; use IEEE.STD_LOGIC_arith.all; ENTITY alu is port (a,b:in std_logic_vector(3 downto 0); s:in std_logic_vector(2 downto 0); y:out std_logic_vector(3 downto 0)); end alu; ARCHITECTURE a of alu IS BEGIN With s Select y<= (a+b) when "000", (a-b) when "001", (a and b) when "010", (a or b) when "011", not (a) when "100", (a xor b) when "101", a When Others; END a;

並行敘述When-Else練習 Library IEEE; use IEEE.STD_LOGIC_1164.all; entity logic4 is port( d0,d1,d2,d3 :IN Std_Logic; s:IN Std_Logic_Vector(1 downto 0); y:OUT Std_Logic); end logic4; architecture a of logic4 is begin y <= d0 when S="00" ELSE d1 when S="01" ELSE '1' when S="10" ELSE (d2 AND d3); end a;

並行敘述When-Else練習 library IEEE; use IEEE.std_logic_1164.all; entity logic5 is port (a,b,c: in std_logic; s: in std_logic_vector (1 downto 0); y0,y1: out std_logic); end logic5; architecture a of logic5 is begin y0 <= (a or b) and (not c); y1 <=(a xor b) when s= "11" else C when s="10" else (b and c); end a;