LIBRARY IEEE;  -- 2003/7/21   GWDVPB
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY gwdvpb IS
    PORT (CLK0 : IN STD_LOGIC; --CLOCK0 標準頻率時鐘信號
          TCLK : IN STD_LOGIC; --PIO27 待測頻率時鐘信號
           CLR : IN STD_LOGIC; --PIO0 清零和初始化信號
            CL : IN STD_LOGIC; --PIO1 當SPUL為高電平時，CL為預置門控信號，用于測頻計數時間控制
                               --當SPUL為低電平時，CL為測脈寬控制信號，CL高電平時測高電平脈寬
                               --而當CL為低電平時，測低電平脈寬。
          SPUL : IN STD_LOGIC;     --PIO2 測頻或測脈寬控制
         START : OUT STD_LOGIC; --PIO2
          EEND : OUT STD_LOGIC; --PIO3 由低電平變到高電平時指示脈寬計數結束，
           SEL : IN STD_LOGIC_VECTOR(2 DOWNTO 0); --PIO6/PIO5/PIO4
                                             --兩個32位計數器計數值分8位讀出多路選擇控制
          DATA : OUT STD_LOGIC_VECTOR(7 DOWNTO 0); --PIO8/9/10/11/12/13/14/15 8位數據讀出
        
          CONT : OUT STD_LOGIC --計數分頻
			
                        );
END ;
ARCHITECTURE behav OF gwdvpb IS
    SIGNAL BZQ  : STD_LOGIC_VECTOR(31 DOWNTO 0);  --標準計數器
    SIGNAL TSQ  : STD_LOGIC_VECTOR(31 DOWNTO 0);  --測頻計數器
    SIGNAL ENA  : STD_LOGIC;   -- 計數使能
    SIGNAL CNT  : STD_LOGIC_VECTOR(15 DOWNTO 0); 
 
    SIGNAL BCLK,LL : STD_LOGIC;
    SIGNAL  MA  : STD_LOGIC;  
    SIGNAL CLK1,CLK4 : STD_LOGIC;
    SIGNAL CLK2 : STD_LOGIC;
    SIGNAL CLK3 : STD_LOGIC;
    SIGNAL   Q1 : STD_LOGIC;
    SIGNAL   Q2 : STD_LOGIC;
    SIGNAL   Q3 : STD_LOGIC;
    SIGNAL BENA : STD_LOGIC;
    SIGNAL  PUL : STD_LOGIC;  --脈寬計數使能

    SIGNAL   SS : STD_LOGIC_VECTOR(1 DOWNTO 0);

  BEGIN
    START <= ENA ;

    DATA <= BZQ(7  DOWNTO  0)  WHEN SEL = "000"  ELSE  -- 標準頻率計數低8位輸出
            BZQ(15 DOWNTO  8)  WHEN SEL = "001"  ELSE
            BZQ(23 DOWNTO 16)  WHEN SEL = "010"  ELSE
            BZQ(31 DOWNTO 24)  WHEN SEL = "011"  ELSE  -- 標準頻率計數最高8位輸出
  
            TSQ(7 DOWNTO   0)  WHEN SEL = "100"  ELSE  --待測頻率計數值最低8位輸出
            TSQ(15 DOWNTO  8)  WHEN SEL = "101"  ELSE
            TSQ(23 DOWNTO 16)  WHEN SEL = "110"  ELSE
            TSQ(31 DOWNTO 24)  WHEN SEL = "111"  ELSE  --待測頻率計數值最高8位輸出
            TSQ(31 DOWNTO 24)  ;
      
-- HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

 BZH :  PROCESS(BCLK, CLR)                    --標準頻率測試計數器，標準計數器
      BEGIN
        IF CLR = '1' THEN   BZQ <= ( OTHERS=>'0' ) ;
        ELSIF BCLK'EVENT AND BCLK = '1' THEN
            IF BENA = '1' THEN   BZQ <= BZQ + 1;   
            END IF;
        END IF;
    END PROCESS;

-- gggggggggggggggggggggggggggggggggggggggggggggggggggg

 TF : PROCESS(TCLK, CLR, ENA)                      --待測頻率計數器，測頻計數器
     BEGIN
       IF CLR = '1' THEN   TSQ <= ( OTHERS=>'0' );
       ELSIF TCLK'EVENT AND TCLK = '1' THEN
           IF ENA = '1' THEN   TSQ <= TSQ + 1;   
           END IF;
       END IF;
   END PROCESS;

--FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

 PROCESS(TCLK,CLR)   --計數控制使能觸發器，CL為預置門控信號，同時兼作正負脈寬測試控制信號
      BEGIN
       IF CLR = '1' THEN   ENA <= '0' ;
        ELSIF TCLK'EVENT AND TCLK = '1' THEN
               ENA <= CL ;   
       END IF;
    END PROCESS;

--OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
  MA  <= (TCLK AND CL) OR NOT(TCLK OR CL)  ; --測脈寬邏輯
 CLK1 <= NOT MA ; 
 CLK2 <= MA AND Q1 ;
 CLK3 <= NOT CLK2  ;
   SS <= Q2 & Q3 ;
-- HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
 DD1:  PROCESS(CLK1,CLR)   
         BEGIN
           IF CLR = '1' THEN   Q1 <= '0' ;
             ELSIF CLK1'EVENT AND CLK1 = '1' THEN  Q1 <= '1' ;   
           END IF;
       END PROCESS;

DD2:  PROCESS(CLK2,CLR)   
         BEGIN
           IF CLR = '1' THEN   Q2 <= '0' ;
             ELSIF CLK2'EVENT AND CLK2 = '1' THEN  Q2 <= '1' ;   
           END IF;
      END PROCESS;

DD3:  PROCESS(CLK3,CLR)   
         BEGIN
           IF CLR = '1' THEN   Q3 <= '0' ;
             ELSIF CLK3'EVENT AND CLK3 = '1' THEN  Q3 <= '1' ;   
           END IF;
      END PROCESS;
-- HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
GT :
    PUL <= '1' WHEN SS = "10" ELSE  --當SS=“10”時，PUL高電平，允許標準計數器計數，
           '0' ;                    --禁止計數

   EEND <= '1' WHEN SS = "11" ELSE  --EEND為低電平時，表示正在計數，由低電平變到高電平
           '0' ;                    --時，表示計數結束，可以從標準計數器中讀數據了
--UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
  BENA <= ENA WHEN SPUL = '1' ELSE  --標準計數器時鐘使能控制信號，當SPUL為1時，測頻率
          PUL WHEN SPUL = '0' ELSE  --當SPUL為0時，測脈寬和占空比
          PUL ;
--UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
-- 標準頻率分頻
  PROCESS(CLK0)   
       BEGIN
         IF  CLK0'EVENT AND CLK0 = '1' THEN  CLK4 <= NOT CLK4 ;   
           END IF;
	 
       END PROCESS;
---TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
 PROCESS(CLK4)   
       BEGIN
         IF  CLK4'EVENT AND CLK4 = '1' THEN  BCLK <= NOT BCLK ;   
           END IF;
	 
       END PROCESS;
 -- UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
PROCESS(BCLK)
BEGIN
IF BCLK'EVENT AND BCLK='1' THEN
LL<=NOT LL;
END IF;
END PROCESS;
  CONT<=LL;

END behav;