TLC7524接口電路程序
--文件名：TLC7524.VHD
--功能：產(chǎn)生156.25KHz的正弦波。
--最后修改日期：2004.3.18。
library ieee;
use ieee.std_logic_arith.all;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity TLC7524 is
? port( clk??? :in std_logic;????????????????????????????????????? --系統(tǒng)時鐘
?????? rst??? :in std_logic;????????????????????????????????????? --復(fù)位信號
????? data_out:out std_logic_vector(7 downto 0));??????????????????? --波形數(shù)據(jù)
? end TLC7524;??????
architecture behav of TLC7524 is
signal b:integer range 0 to 63;??????????????????????????????????? --地址計數(shù)器
signal q:integer range 0 to 4;???????????????????????????????????? --計數(shù)器
signal d:integer range 0 to 255;?????????????????????????????????? --波形數(shù)據(jù)寄存器
begin
process(clk)????????????? --此進程通過對系統(tǒng)時鐘的分頻，完成的地址計數(shù)器的循環(huán)計數(shù)
begin
if rst='1' then b<=0;????????????????????????????????????? --復(fù)位時，對地址寄存器清零??
elsif clk'event and clk='1' then
?? if q=4 then q<=0;???????????????????????????? --此IF語句完成對系統(tǒng)時鐘的5分頻
????? if b=63 then b<=0;????????????????????????? --此IF語句完成對地址的循環(huán)計數(shù)
????? else b<=b+1;
????? end if;
?? else q<=q+1;
?? end if;
end if;
end process;
process(b)????????????????????????????? --此進程存儲了正弦波64個采樣點的波形數(shù)據(jù)
begin
case b is
when 00=> d<=255? ; when 01=> d<=254? ;when 02=> d<=252? ;when 03=> d<=249? ;
when 04=> d<=245? ; when 05=> d<=239? ;when 06=> d<=233? ;when 07=> d<=225? ;
when 08=> d<=217? ; when 09=> d<=207? ;when 10=> d<=197? ;when 11=> d<=186? ;
when 12=> d<=174? ; when 13=> d<=162? ;when 14=> d<=150? ;when 15=> d<=137? ;
when 16=> d<=124? ; when 17=> d<=112? ;when 18=> d<= 99? ;when 19=> d<= 87? ;
when 20=> d<= 75? ; when 21=> d<= 64? ;when 22=> d<= 53? ;when 23=> d<= 43? ;
when 24=> d<= 34? ; when 25=> d<= 26? ;when 26=> d<= 19? ;when 27=> d<= 13? ;
when 28=> d<=? 8? ; when 29=> d<=? 4? ;when 30=> d<=? 1? ;when 31=> d<=? 0? ;
when 32=> d<=? 0? ; when 33=> d<=? 1? ;when 34=> d<=? 4? ;when 35=> d<=? 8? ;
when 36=> d<= 13? ; when 37=> d<= 19? ;when 38=> d<= 26? ;when 39=> d<= 34? ;
when 40=> d<= 43? ; when 41=> d<= 53? ;when 42=> d<= 64? ;when 43=> d<= 75? ;
when 44=> d<= 87? ; when 45=> d<= 99? ;when 46=> d<=112? ;when 47=> d<=124? ;
when 48=> d<=137? ; when 49=> d<=150? ;when 50=> d<=162? ;when 51=> d<=174? ;
when 52=> d<=186? ; when 53=> d<=197? ;when 54=> d<=207? ;when 55=> d<=217? ;
when 56=> d<=225? ; when 57=> d<=233? ;when 58=> d<=239? ;when 59=> d<=245? ;
when 60=> d<=249? ; when 61=> d<=252? ;when 62=> d<=254? ;when 63=> d<=255? ;
when others=> null;
end case;
end process;
data_out<=conv_std_logic_vector(d,8);?????????????????????? --正弦波波形數(shù)據(jù)輸出
end behav;