state_machine.vhd

sdram控制器

--###############################################################################
--
--  LOGIC CORE:          SDR SDRAM Controller state machine							
--  MODULE NAME:         state_machine()                  	
--  date:		 2006.8.07
--  REVISION HISTORY:  
--  FUNCTIONAL DESCRIPTION:
--
--  This module is the state_machine for the SDR SDRAM controller.
--  Copyright (C) 1991-2000 
--##############################################################################
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity state_machine is
       port (
               sdramclk       : in       std_logic;                            --系统时钟由 pll产生，100mhz     
               operationreq   : in       std_logic_vector(2 downto 0);         --操作请求码，对应各种操作
               CMDACK         : in       std_logic;                            --Controller command acknowledgement
               cmdstate       : out      std_logic_vector(3 downto 0);         --输出当前的状态
	       						 -- 命令长度计数器的返回值
		tcmdlengthcount : out      std_logic_vector(9 downto 0);
	       cmd            : inout      std_logic_vector(2 downto 0);         --输出给sdramcontroller的命令端口
	       reset          : in       std_logic;			       --模块的复位信号
	       reqack         : out      std_logic;                            --操作完成应答信号，10ns的脉冲
	       fifo1rden	      : out      std_logic;			       --fifo的使能信号高电平有效
	       fifo2wren	      : out      std_logic;
		hostdataen	      : out      std_logic;
		--ackcounti         :out std_logic_vector(2 downto 0);
		
	       counto5         : out      std_logic_vector(2 downto 0);
	       counto3         : out      std_logic_vector(2 downto 0)
);
end state_machine;
architecture operation of state_machine is

--signal   cmdlengthcounti  : std_logic_vector(9 downto 0):="0000000000";        --计数器
signal   cmdlengthcountii  : std_logic_vector(9 downto 0):="0000000000";        --计数器
signal   cmdstatei        : std_logic_vector(3 downto 0):="0000";
signal   count1           : std_logic_vector(2 downto 0):="000";
signal   count2           : std_logic_vector(2 downto 0):="000";
signal   count3           : std_logic_vector(2 downto 0):="000";
signal   count4           : std_logic_vector(2 downto 0):="000";
signal   count5           : std_logic_vector(2 downto 0):="000";
signal   ackcount         : std_logic_vector(2 downto 0):="000";

signal   stopcount        : std_logic;
signal   operationreqi         : std_logic_vector(2 downto 0):="000";
signal   opq         : std_logic_vector(5 downto 0):="000000";
begin
tcmdlengthcount<=cmdlengthcountii;
--cmdlengthcount <= cmdlengthcounti;
cmdstate <= cmdstatei;

--counto1 <= count1;
counto5 <= count5;

counto3 <= count3;
--ackcounti <=ackcount; 
process(reset,CMDACK,ackcount,sdramclk,cmdstatei)
begin
	if(reset = '0' or cmdstatei="0000") then
		stopcount <= '0';
	else	 
	  if rising_edge(sdramclk) then
	   if(ackcount<="001") then
		if(CMDACK='1') then
			stopcount <= '0';
		else
			stopcount <= '1';
		end if;
	   else
		stopcount <= '1';
	   end if;
	end if;
	end if;	
end process;

process(reset,sdramclk,cmdstatei) 			--第一次ack后的计数器
 begin 
 if (reset = '0' or cmdstatei="0000" ) then 
	--cmdlengthcounti<="0000000000";
	cmdlengthcountii <= "0000000000";
 else
	if rising_edge(sdramclk) then
		if(ackcount="001") then
 			cmdlengthcountii <= cmdlengthcountii+1;
		else
			
			cmdlengthcountii <= "0000000000";
		end if;
	end if;
 end if;
end process;
process(reset,CMDACK,cmdstatei,sdramclk)					--记录每一种操作的cmdack的个数
	begin
		if(reset = '0' or cmdstatei="0000") then
			ackcount <= "000";
		else
			if rising_edge(sdramclk) then
			 	if(CMDACK = '1') then
			   		ackcount <= ackcount+1;
				end if;
			end if;
		end if;	
end process;
process(reset,ackcount,sdramclk,cmdstatei)		--第3次ack后的计数器(无用)
	begin
		if(reset = '0' or cmdstatei="0000") then
			count1 <= "000";
		else
			if rising_edge(sdramclk) then
				--if (ackcount="001") then
				if (ackcount="011") then
		   		   count1 <= count1+1;
				else
				count1 <= "000";	
		   		end if;
			end if;
		end if;	
end process;
process(reset,ackcount,sdramclk,cmdstatei)		--第4次ack后的计数器(无用)
	begin
		if(reset = '0' or cmdstatei="0000") then
			count2 <= "000";
		else
			if rising_edge(sdramclk) then
				--if (ackcount="010") then
				if (ackcount="100") then
		   		   count2 <= count2+1;
				end if;
		   	end if;
		end if;	
end process;

process(reset,ackcount,sdramclk,cmdstatei)		--第1次ack后的计数器 用来锁存数据使用
	begin
		if(reset = '0' or cmdstatei="0000") then
			count3 <= "000";
		else
			if rising_edge(sdramclk) then	
				if (ackcount="001" ) then		   	   	 	
					count3 <= count3+1;
					
				end if;
		        end if;
		end if;	
end process;

process(reset,ackcount,sdramclk,cmdstatei)		--第1次ack后的计数器
	begin
		if(reset = '0' or cmdstatei="0000") then
			count4 <= "000";
		else
			if rising_edge(sdramclk) then	
				if (ackcount="010") then
		   	   	 count4 <= count4+1;
				end if;
		        end if;
		end if;	
end process;
process(reset,ackcount,sdramclk,cmdstatei)		--第1次ack后的计数器
	begin
		if(reset = '0' or cmdstatei="0000") then
			count5 <= "000";
		else
			if rising_edge(sdramclk) then	
				if (ackcount <="000") then
		   	   	 	count5 <= count5+1;
				else
					count5 <= "000";	
				end if;
		        end if;
		end if;	
end process;
process(operationreq,sdramclk)

begin

	if rising_edge(sdramclk) then

		operationreqi <= operationreq;

	end if;

end process;
opq <= operationreq & operationreqi;

process(reset,opq,sdramclk,CMDACK,ackcount,cmdstatei,cmdlengthcountii)
   variable ackcount1 :std_logic_vector(9 downto 0);
   
	begin
	 if(reset = '0') then
	    cmdstatei <= "0000";
		  cmd <="000";
		  reqack <= '0';
		  fifo1rden <='0';
		  fifo2wren <='0';
		  hostdataen <='0';
	 else
	   if rising_edge(sdramclk) then
		case cmdstatei is
		    when "0000" =>
			case opq is
			  when "000000" =>            	--idle
				cmdstatei <= "0000";
			  when "001000" =>            	--页写
				cmdstatei <= "0001";
			  when "010000" =>			--页读
				cmdstatei <= "0010";
			  when "011000" =>			--随机写
				cmdstatei <= "0011";
			  when "100000" =>			--机读
				cmdstatei <= "0100";
			  when "101000" =>			--页配置
				cmdstatei <= "0101";
			  when "110000" =>			--随机配置
				cmdstatei <= "0110";
			  when "111000" =>			--refresh
				cmdstatei <= "0111";
			  when others =>NULL; 
			  end case;
			  cmd <="000";
			  reqack <= '0';
			  fifo1rden <='0';
			  fifo2wren <='0';
			  hostdataen <='0';
----------页写请求操作(完成!)------------------------------------------	
		   when  "0001" =>				--page write
			
			if(count5="001") then
				cmd <= "010";
			elsif(CMDACK='1'and cmd = "010") then
				cmd <= "000";
			elsif(count4 = "011") then
				cmd <="100";
			elsif(cmdlengthcountii=508) then
				cmd <= "100";
			end if;
						
			if(cmdlengthcountii <= "0111111111" and cmdlengthcountii>="0000000000" and ackcount="001") then
				fifo1rden<= '1' ;
			else
				fifo1rden<= '0' ;
			end if;
			
			if(ackcount>="011") then
				cmdstatei <= "0000";
			   	reqack <= '1';
			end if;					 
			        		
---------页读请求操作(完成!)--------------------------------------------						
		   when   "0010" =>		                    --page READ

			if(count5="001") then
				cmd <= "001";
			elsif(CMDACK='1'and cmd = "001") then
				cmd <= "000";
			elsif(count4 = "011") then
				cmd <="100";
			elsif(cmdlengthcountii=508) then
				cmd <= "100";
			end if;
			if(cmdlengthcountii <= 519 and cmdlengthcountii>=4 and ackcount="001") then
				fifo2wren<= '1' ;
			else
				fifo2wren<= '0' ;
			end if;
			
			if(ackcount>="011") then                    --第三个ack后结束本次页写操作
			   	cmdstatei <= "0000";
			   	reqack <= '1';
			end if;

			
----------随机写请求操作(完成!)------------------------------------------
		  when   "0011" =>				--write	 burst length=1											

			if(count5="001") then
				cmd <= "010";
			elsif(CMDACK='1'and cmd = "010") then
				cmd <= "000";
			end if;
			if(cmdlengthcountii < 1 and cmdlengthcountii>=0 and ackcount="001") then
				hostdataen<= '1' ;
			else
				hostdataen<= '0' ;
			end if;
			if(cmdlengthcountii >10) then
				reqack <= '1';
				cmdstatei <= "0000";			
			end if;
-------------------------------------------------------
			 
			
--------------------随机读请求操作(完成！)----------------------------------			
		when   "0100" =>				--read burst length=1																

			if(count5="001") then
				cmd <= "001";
			elsif(CMDACK='1'and cmd = "001") then
				cmd <= "000";
			end if;
			if(cmdlengthcountii < 8 and cmdlengthcountii>=7 and ackcount="001") then
				hostdataen<= '1' ;
			else
				hostdataen<= '0' ;
			end if;
			if(cmdlengthcountii >10) then
				reqack <= '1';
				cmdstatei <= "0000";			
			end if;
--------------------------------------		
----------------页配置操作模式(完成!)-------------------------------------			
		    when   "0101" =>

			if(count5="001") then
				cmd <= "100";			   	--precharge
			elsif(cmdack='1' and cmd="100") then 
			        cmd <= "011";				--precharge
			elsif(ackcount="010" and cmd="011") then   
			        cmd <= "011";				--precharge
			elsif(cmd = "011" and ackcount="011" ) then 	--load_mode_reg		   
				cmd <="101";						  														
			elsif(ackcount="100") then
				cmd <= "000";
			  	cmdstatei <= "0000";
				reqack <= '1';			
			end if;	
---------------------------------------------------------------------------
----------------随机配置操作模式(完成!)-------------------------------------			
		    when   "0110" =>
		
			if(count5="001") then
				cmd <= "100";			   	--precharge
			elsif(cmdack='1' and cmd="100") then 
			        cmd <= "011";				--precharge
			elsif(ackcount="010" and cmd="011") then   
			        cmd <= "011";				--precharge
			elsif(cmd = "011" and ackcount="011" ) then 	--load_mode_reg		   
				cmd <="101";						  														
			elsif(ackcount="100") then
				cmd <= "000";
				reqack <= '1';
			  	cmdstatei <= "0000";
							
			end if;		
-----------------------------------------------------------
		   when   "0111" =>
			
			if(count5="001") then
				cmd <= "011";
			elsif(CMDACK='1') then   
			        cmd <= "000";
				cmdstatei <= "0000";
				reqack <= '1';
			end if;	
	 	  when others =>NULL;	
			--when others =>
			--	reqack <= '0';				
	end case;
  end if;
end if;
end process;

end operation;