clkrecoverydpll.vhd

用于时钟恢复的全数字锁相环设计

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

entity clkrecvy is
port
        (
        clockin  : in std_logic ; --change type inout to in
        clockout : out std_logic ;   
        datain   : in std_logic ;
        dataout  : out std_logic ;
	ctrl	 : in std_logic_vector(2 downto 0);
	clk32mlocal : in std_logic 
    );
begin
end clkrecvy;

architecture structure of clkrecvy is

signal pdcounter: std_logic_vector(5 downto 0);
signal pdcounterresult:std_logic_vector(5 downto 0);
signal tempclockin: std_logic;
signal clockout1: std_logic;
signal dataout1: std_logic;
signal dteclkrecvydiv:std_logic_vector(4 downto 0);
signal dteclkrecvy: std_logic;
signal dteclkrecvyallspeed: std_logic;
signal dteclkrecvyallspeeddelay: std_logic;
signal dteclkrecvyallspeeddelay2: std_logic;
signal pllcountertosave:std_logic;
signal pllpd2: std_logic;
signal cnt:std_logic_vector(3 downto 0);
signal delete: std_logic;
signal temp1:std_logic;
signal temp2: std_logic;
signal pd: std_logic;

begin

process (clockin,clk32mlocal) --to generate the reset signal
begin
	if (clk32mlocal'event) and (clk32mlocal='1') then
		tempclockin<=clockin;
	end if;
end process;

process(dteclkrecvy)  --to help the other speeds. 
begin
	if (dteclkrecvy'event) and (dteclkrecvy='1') then
		dteclkrecvydiv<=dteclkrecvydiv+1;
	end if;
end process;
		 -----no use 000 because 2m just pass through dteclkrecvydiv(0) when (ctrl="000") else
process(dteclkrecvy)
begin
	if (dteclkrecvy'event) and (dteclkrecvy='1') then
		dteclkrecvyallspeeddelay<=dteclkrecvyallspeed;---delay once
		dteclkrecvyallspeeddelay2<=dteclkrecvyallspeeddelay;-----delay twice is a phase dector d flip flop clear signal
	end if;
end process;

process(pllcountertosave)
begin
	if (pllcountertosave'event) and (pllcountertosave='1') then
		pdcounterresult<=pdcounter;
	end if;
end process;

process(pllpd2,tempclockin)
begin
	if (pllpd2='1') then------this is a d flip flop with reset port
		pd<='0';
	elsif (tempclockin'event) and (tempclockin='1') then
		pd<='1';
	end if;
end process;

process(clk32mlocal)
begin
	if (clk32mlocal'event) and (clk32mlocal='1') then
		if(pd='0') then   --phase detector signal is zero, pd counter reset.
			pdcounter<="000000";
	       	elsif(pd='1') then
			if (pdcounter="111111") then
			    pdcounter<="111111";
			else
				pdcounter<=pdcounter+1;
			end if;
		end if;
	end if;
end process;

process(clk32mlocal)
begin
	if(pllpd2='0') then
		temp1<='0';
		temp2<='0';
	elsif (clk32mlocal'event) and (clk32mlocal='1') then
		if ((pdcounterresult(3)='0') and (pdcounterresult(4)='0') and (pdcounterresult(5)='0')) then
			temp1<='1';
			temp2<=temp1;
		end if;
	end if;
end process;

process(clk32mlocal)
begin
	if (clk32mlocal'event) and (clk32mlocal='1') then
		if (delete='0') then  ----/17 shiji wei kou pulse
			if ((pdcounterresult(3)='1') and (pdcounterresult(4)='1') and (pdcounterresult(5)='1')) then
					cnt<=cnt+2;  --/15 to track faster
			else cnt <=cnt+1;  --/16 normal operation
			end if;
		end if;
	end if;
end process;

process(clockout1)
begin
	if (clockout1'event) and (clockout1='1') then
		dataout1<=datain;
	end if;
end process;

dteclkrecvyallspeed<= dteclkrecvydiv(0) when (ctrl="001") else
			 dteclkrecvydiv(1) when (ctrl="010") else
			 dteclkrecvydiv(2) when (ctrl="011") else
			 dteclkrecvydiv(3) when (ctrl="100") else
			 dteclkrecvydiv(4);
		
pllcountertosave <= dteclkrecvyallspeed and (not dteclkrecvyallspeeddelay);  --to save the pd counter
pllpd2<=dteclkrecvyallspeeddelay and (not dteclkrecvyallspeeddelay2);  -- to clear the d flip flop

delete<= temp1 and (not temp2);

dteclkrecvy<=cnt(3);

clockout1<=dteclkrecvy;

clockout<=clockin when ctrl= "000" else
		  clockout1;
dataout <=datain when ctrl= "000" else
     	  dataout1;

end structure;