|
LIBRARY ieee; 6 Z8 A& _( U1 w# ~# r! f
USE ieee.std_logic_1164.all;$ s+ J8 W7 D+ Y0 b7 w% f/ Y- o
USE ieee.std_logic_unsigned.all;
) [! A; y0 U) j' |, I9 uENTITY counter_backwards60_seg2 IS; o# O0 g: Z" G
PORT(Clk : IN STD_LOGIC;
0 A8 c( T- W6 e8 ^+ q Q0,Q1 : OUT STD_LOGIC_VECTOR(3 downto 0)) ; ' `: M( o9 H5 W# |, U% X
END counter_backwards60_seg2;( U1 |6 I1 v# W, A8 G" Y; q
ARCHITECTURE arc OF counter_backwards60_seg2 IS3 V0 e) N7 ~: m+ C. E+ a' s
BEGIN
1 f- A- Y9 u/ c A7 O6 x1 L A" l. x PROCESS (Clk)
' n4 N9 {+ u# v, i VARIABLE imper0 :STD_LOGIC_VECTOR(3 downto 0);
1 k9 R7 C( T" b# A+ Q5 o. J) d VARIABLE imper1 :STD_LOGIC_VECTOR(3 downto 0); ) |. |1 \3 w8 @ n: g
BEGIN
! {% ]. M0 W& W
7 f5 g! g, s8 O: | IF (Clk'event AND Clk='1') THEN
/ n/ }1 _0 n D( A5 T; Z- o
0 Y1 l0 b" u: X N IF imper0 >"0000" THEN imper0 := imper0-1;2 R0 X+ X: f' }( q }: [
ELSE imper0:="1001";( }) ]$ \1 l3 p, m1 j6 K( H
IF imper1 >"0000" THEN imper1 := imper1-1;
0 p5 o$ Q. q4 a3 [, O e1 Y! _ ELSE imper1:="0101"; 8 D* y% [6 t* z" H* D# _# S
END IF;
& z4 t* Q7 H0 R+ |# s. ~5 b END IF;
$ w& h' y3 C% I2 c. x# V/ y: t END IF;
. c U0 Z' c. @: R) l$ E! g9 ] Q0 <= imper0; Q1 <= imper1;
y# E: O' V. Q, M s END PROCESS ;
$ i, l- O, b- A( F: ~ s2 L D% O9 K3 `END arc;
" o1 U( H4 @3 H以上我精簡了一些 也能跑模擬圖( q4 l3 x* i! x* a1 W6 ~9 l6 Q0 {
但現在重點是我該怎寫60→59→58...1 r) F! t" Y# T6 B
初始值60要怎寫...
# R0 M9 s& H p G4 s1 M! m) k8 V4 v8 w9 I是要多2個input 然後給他一開始的值?
- j8 e' n, Q6 h但要怎寫啊@@...
, C' F4 v* p! O$ ~ |5 D |
|