分频器设计4

?K!dr1BO|0           奇数分频器设计EDA中国门户网站6XT#@PC
           占空比不为1:1的奇数分频器

           占空比不为1:1的奇数分频器的实现方法与占空比不为1:1的偶数分频器相同。EDA中国门户网站X"mKM8w)YG

:};BXq5X'fl4D\Pr0           例：设计一个占空比为1:2的3分频电路。EDA中国门户网站(kF yJMN/dc

S-mu4~IN!fo+W0           ENTITY cnt4 IS
x wUDgz p!f0                 PORT(clk    : IN      STD_LOGIC;
S0O'v5X'f Bn$Y0                              div3 : OUT  STD_LOGIC);
'EQ_K#v2a N0           END cnt4;EDA中国门户网站U'v6S;Yu9A%K

J{"ehd.yL0           ARCHITECTURE divcnt OF cnt4 IS
zXk{4v2]0                 SIGNAL temp : STD_LOGIC_VECTOR(1 DOWNTO 0);
iln6j?S0                 CONSTANT cst : STD_LOGIC_VECTOR(1 DOWNTO 0) := "10";
P0@!p,A7hR o;TcN0           BEGINEDA中国门户网站Hyc1o7fM

,j [:iA*S-_"Nh%fy0                 p1:PROCESS(clk)
5Cj2J&Z`N2k;P4m0                     BEGIN
c$dBvd0d.C0                          IF(clk"EVENT AND clk = '1') THENEDA中国门户网站@
l0@)]D
                             IF(temp = cst) THEN
\qTzJ x0                                temp <= (OTHERS => '0');
PU UD&Z-Wd0                             ELSEEDA中国门户网站:|wz-p3CX
                                temp <= temp + 1;
Zov.Vv5MI'VE0                             END IF;EDA中国门户网站} rydG5\TrOt
                        END IF;
[$Q r2B[&t1MlR]$S:f0                     END PROCESS;EDA中国门户网站6PU@5|.h

                  p2:PROCESS(clk)
Y#[h X{?+oeu0                       BEGINEDA中国门户网站 w.r2|%v$A~B
                            IF(clk'EVENT AND clk = '1') THEN
~R"GQ,u,gPW7H"SX0                               IF(temp < 1) THENEDA中国门户网站K"K/aX)V:uG
                                   div3 <= '1';
V?z3^p.w0                               ELSEEDA中国门户网站[2n'i y:Q*dN$h6yN`t
                                    div3 <= '0';
9LPl iyp|'b'Y0                               END IF;EDA中国门户网站I\ gVj6CK L^
                             END IF;EDA中国门户网站.s:x}*T,[8rH3C V
                          END PROCESS;
WR]C`~RJ[0               END divcnt;EDA中国门户网站{
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