p; end if;
end if;
end if;
end if;
if count1=12499999 then count1:=0; --调方波A的占空比
if zu='1' then
if z<63 then z<=z+1;
else z<=63;
end if;
elsif zd='1' then
if z>0 then z<=z-1;
else z<=0;
end if;
end if;
else count1:=count1+1;
end if;
if count0=3249999 then count0:=0;
--up、down对4种波形幅度调节，u0、d0进一步对方波进行幅度调节
if u0='1' then
if amp0<"11111111" then amp0<=amp0+1;
else amp0<="11111111";
end if;
elsif d0='1' then
if amp0>"00000000" then amp0<=amp0-1;
else amp0<="00000000";
end if;
elsif up='1' then
if amp<"11111111" then amp<=amp+1;
else amp<="11111111";
end if;
elsif down='1' then
if amp>"00000000" then amp<=amp-1;
else amp<="00000000";
end if;
end if;
else count0:=count0+1;
end if;
end if;
end if;
end if;
end process;
a<=amp; --将幅值输出。
cov_a:process(clk,amp,amp0)
--主要实现各波形幅度值到BCD码的转化，由于方波和其他三种波形的幅度调节方式、精
--度不同，因此对幅度的处理方式分两种：“sss="00010" or sw='1'”是判断输出波形是否为
--方波（A或B），bcd00,bcd10,bcd20,bcd30是本进程的输出。
variable count : integer range 0 to 50004225;
variable counter : integer range 0 to 500055;
variable count1,count0 : integer range 0 to 4999999;
begin
if rising_edge(clk) then
if sss="00010" or sw='1' then count0:=0; --方波
if count1=4999999 then count1:=0; bcd0<=0; bcd1<=0; bcd2<=0; bcd3<=0;
count:=(conv_integer(amp))*(conv_integer(amp0))*769; --幅值运算
elsif count1=4999900 then count1:=count1+1;
bcd00<=bcd0; bcd10<=bcd1; bcd20<=bcd2; bcd30<=bcd3; --数据输出
else count1:=count1+1; --二进制码到BCD码的数据转换
if count>9999999 then count:=count-10000000; bcd0<=bcd0+1;
elsif count>999999 then count:=count-1000000; bcd1<=bcd1+1;
elsif count>99999 then count:=count-100000; bcd2<=bcd2+1;
elsif count>9999 then count:=count-10000; bcd3<=bcd3+1;
else null;
end if;
end if;
else count1:=0;
