iic.vhd

自己写的iic配置芯片的源程序

LIBRARY ieee;
USE ieee.std_logic_1164.all;
USE IEEE.STD_LOGIC_ARITH.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY IIC IS 
	PORT
	(
	       DATA     : IN  STD_LOGIC_VECTOR(7 DOWNTO 0);
	       CLK      : IN  STD_LOGIC;--100kHZ
	       CLK2     : IN  STD_LOGIC;--3MHZ,用作延时计数
		   MODE     : IN  STD_LOGIC;--0编码，1解码
		   CONF     : IN  STD_LOGIC;
		   CSDA     : INOUT STD_LOGIC;--数据		
		   CSCL  	: INOUT STD_LOGIC;  --时钟
		 CLKROM     : OUT STD_LOGIC;
		 	 RS     : OUT STD_LOGIC;--重启动信号
		   ADDR     : OUT STD_LOGIC_VECTOR(8 DOWNTO 0);
		  PROBE     : OUT STD_LOGIC_VECTOR(3 DOWNTO 0)
		 -- PROBE2    : OUT STD_LOGIC_VECTOR(3 DOWNTO 0)
	);
END IIC;
architecture art of IIC is
TYPE   STA   IS(S0,S1,S2,S3);
SIGNAL STATE               : STA; -- : INTEGER RANGE 0 TO 3;--四个状态。空，起始，忙，结束
SIGNAL ACK                 : INTEGER RANGE 0 TO 2;
SIGNAL COUNT,DELAY1,DELAY2 : INTEGER RANGE 0 TO 9;--COUNT用于发送bit计数，DELAY用作延时计数
SIGNAL ADD                 : STD_LOGIC_VECTOR(8 DOWNTO 0);
--SIGNAL RS                  : INTEGER RANGE 0 TO 1;

BEGIN
   CSCL<=CLK;
   ADDR<=ADD;
   PROBE <=CONV_STD_LOGIC_VECTOR(COUNT,4);
  -- PROBE2<=CONV_STD_LOGIC_VECTOR(DELAY1,4);

   PROCESS(CLK2,CLK)
     BEGIN 
      IF(CLK='0')THEN
        DELAY1<=0;
     -- IF(CLK='1')THEN
      ELSIF(CLK2'EVENT AND CLK2='1')THEN
          DELAY1<=DELAY1+1;
       -- END IF; 
     END if;
   END PROCESS;

   PROCESS(CLK2,CLK)
     BEGIN 
      IF(CLK='1')THEN
        DELAY2<=0;
      --IF(CLK='0')THEN
      ELSIF(CLK2'EVENT AND CLK2='1')THEN
          DELAY2<=DELAY2+1;
    --    END IF; 
     END if;
   END PROCESS;



   PROCESS(STATE,CLK)
     BEGIN 
       IF(STATE=S0) THEN
         COUNT<=0;
       ELSIF(CLK'EVENT AND CLK='0')THEN
         IF((STATE=S1 OR STATE=S2 )) THEN --总在低电平时发信号
          COUNT<=COUNT+1;
         ELSIF( STATE=S3) THEN --总在低电平时发信号
          IF(ACK<2)THEN
          COUNT<=1;
          ELSE
          COUNT<=0;
          END IF;
         END IF;
      END if;
   END PROCESS;

   PROCESS(CONF,COUNT,ACK)
    BEGIN 
     IF(CONF='0') THEN
         STATE<=S0;
     ELSE
        IF(CLK2'EVENT AND CLK2='1')THEN
       IF(COUNT=9)THEN
           STATE<=S3;
        ELSIF(COUNT=0 )THEN--起始信号，较时钟上升沿再后一点
           STATE<=S1;--TINGZHI
        ELSE
           STATE<=S2;
        END IF;
     END IF;
      END IF;
   END PROCESS;
   
   PROCESS(STATE,DELAY1,DELAY2,DATA,COUNT)
 --   VARIABLE CNT :INTEGER RANGE 0 TO 9;
    BEGIN 
 --     CNT:=COUNT;
      CASE STATE IS 
       WHEN S0 =>
        CSDA<='1';
       WHEN S1 =>
        IF (DELAY1>1) THEN
          CSDA<='0';
     --   ELSE
      --  CSDA<='1';
        END IF;
       WHEN S2 =>
        IF DELAY2>1 THEN
          CSDA<=DATA(8-COUNT);
        END IF;
       WHEN S3=>
            CSDA<='Z';
      END CASE;
    --  IF(STATE=0)THEN
    --    CSDA<='1';
      
    --  ELSIF(STATE=1 AND DELAY1=2)THEN 
    --    IF(DELAY1>1 )THEN
     --      CSDA<='0';
  --     ELSE
      --     CSDA<='1';
     --    END IF;
    --  ELSIF(STATE=2)THEN
    --    IF(DELAY2>1)THEN
     --    CSDA<=DATA(8-COUNT);
     --   END IF;
    
   --  ELSIF(STATE=3)THEN
   --   ELSE
     --  CSDA<='Z';
   --   END IF;
   END PROCESS;
  
   PROCESS(STATE,CLK,CSDA)
     BEGIN 
   --    ADDR<=ADD;
      IF(STATE=S3)THEN
 --        ADD<="0000";
       IF(CLK'EVENT AND CLK='1')THEN
        IF(CSDA='0')THEN
         ADD<=ADD+'1';
       --  ADDR<=ADD; 
        ELSE
         ADD<="000000000";
    --    CLKROM<='1';      
         END IF;
        END IF;
      END IF;
 --  ADD<=TMP;
   END PROCESS;

   PROCESS(STATE,CSDA,CLK,DELAY1)
     BEGIN 
      IF(STATE=S3)THEN
    --  IF(DELAY1>1)THEN
        IF(CSDA='1')THEN
          IF(DELAY1>3)THEN
            ACK<=2;--no确认
           END IF;
        ELSE
     --    IF(DELAY1>3)THEN
         ACK<=1;--确认
        END IF;
      ELSE
       ACK<=0;
      END IF;
   END PROCESS;

   PROCESS(STATE,CLK2)
     BEGIN 
   --  IF(CLK2'EVENT AND CLK2='1')THEN
      IF(STATE=S2)THEN
      CLKROM<='1';
      ELSE
      CLKROM<='0';
      END IF;
    --  END IF;
   END PROCESS;


--   PROCESS(CONF,ACK,STATE)
 --    BEGIN 
 --  IF(CONF='0')THEN
 --    RS<='0';
 --  ELSE
 --    IF(STATE=S3)THEN
 --     IF(ACK=2)THEN
--       RS<='1';
   --  ELSIF(ACK=1)THEN
    -- RS<='0';
    --  END IF;
 --     ELSE
 --     RS<='0';
 --     END IF;
   --  ELSE
   --  RS<='0';
 --    END IF;
 --  END IF;
---   END PROCESS;

END;