ds18b20.vhd

有關於EP2C的一些程序(EX:I2C,FLASH,IRDA,MUSIC,LED,LIGHT,SRAM,UART,PS2,SPI )

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--*************************************************************************************************
--  CreateDate  :  2007-07-24 
--  ModifData   :  2007-07-26 
--  Description :  DS18B20 ( Asynchronous, Data bits: 16 ) 
--  Author      :  Explorer01 
--  Version     :  V1.0  
--*************************************************************************************************
---------------------------------------------------------------------------------------------------

-- VHDL library Declarations 
LIBRARY IEEE;
USE IEEE.std_logic_1164.ALL;
USE IEEE.std_logic_unsigned.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;

---------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------------------
-- The Entity Declarations 
ENTITY DS18B20 IS
	PORT 
	(
		RESET: IN STD_LOGIC;
		CLK:   IN STD_LOGIC; 
		Fresh: IN STD_LOGIC; 
		
		DQ:    INOUT STD_LOGIC; 
		
		EOC:   OUT STD_LOGIC;
		PDATA: OUT STD_LOGIC_VECTOR(7 DOWNTO 0)
	);
END DS18B20;

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---------------------------------------------------------------------------------------------------
-- The Architecture of Entity Declarations 
ARCHITECTURE Behavioral OF DS18B20 IS
	------------------------------------------------
	CONSTANT STATE_RST1 	:	STD_LOGIC_VECTOR(2 DOWNTO 0) := "000";
	CONSTANT STATE_WRITE1	:	STD_LOGIC_VECTOR(2 DOWNTO 0) := "001";
	CONSTANT STATE_READ		:	STD_LOGIC_VECTOR(2 DOWNTO 0) := "010";
	
	CONSTANT STATE_RST2 	:	STD_LOGIC_VECTOR(2 DOWNTO 0) := "011";
	CONSTANT STATE_WRITE2	:	STD_LOGIC_VECTOR(2 DOWNTO 0) := "100";
	CONSTANT STATE_WAIT		:	STD_LOGIC_VECTOR(2 DOWNTO 0) := "101";
	
	SIGNAL state : STD_LOGIC_VECTOR(2 DOWNTO 0);
	
	------------------------------------------------
	-- Command for DS18B20 : 0xBECC, 0x44CC 
	CONSTANT COMMAND1 :	STD_LOGIC_VECTOR(15 DOWNTO 0) := B"1011_1110_1100_1100";
	CONSTANT COMMAND2 :	STD_LOGIC_VECTOR(15 DOWNTO 0) := B"0100_0100_1100_1100";
	
	SIGNAL DATA : STD_LOGIC_VECTOR(15 DOWNTO 0);	-- Temperature  
	
	------------------------------------------------
	SIGNAL CLKCNT : STD_LOGIC_VECTOR(5 DOWNTO 0);	-- 64uS 
	SIGNAL CLKRW, CLKread, CLKwrite0, CLKwrite1  : STD_LOGIC; 
	
	SIGNAL Count : INTEGER RANGE 0 TO 20;
	
	------------------------------------------------
	SIGNAL EOCtemp, VALUE : STD_LOGIC; 
	
BEGIN
	
	-------------------------------------------------
	-- State 
	PROCESS( RESET, CLK, CLKCNT, CLKRW, Count, CLKwrite0, CLKwrite1, state, VALUE, Fresh )
	BEGIN
		-----------------------------------------------
		-- The primary period for write and read 
		IF( RESET='0' ) THEN 
			CLKCNT <= "000000";
		ELSIF( CLK'EVENT AND CLK='1' ) THEN 
			CLKCNT <= CLKCNT + 1; 
		END IF; 
		
		CLKRW <= CLKCNT(5); 	-- Period : 64uS 
		
		-----------------------------------------------
		-- Write plus 
		-- Write "0" 
		IF( CLKCNT<61 ) THEN CLKwrite0 <= '0';
		ELSE				 CLKwrite0 <= '1';
		END IF; 
		
		-- Write "1" 
		IF( CLKCNT<5  ) THEN CLKwrite1 <= '0';
		ELSE				 CLKwrite1 <= '1';
		END IF; 
		
		-----------------------------------------------
		-- Read plus 
		IF( CLKCNT<14 ) THEN CLKread <= '0';
		ELSE				 CLKread <= '1';
		END IF; 
		
		--=============================================
		-- Update the state 
		IF( RESET='0' ) THEN 
			state <= STATE_RST1; 
			Count <= 0;
		ELSIF( CLKRW'EVENT AND CLKRW='0' ) THEN 
			CASE state IS 
				-----------------------------------
				-- RESET 
				WHEN STATE_RST1 => 
					IF( Count>20 ) THEN Count <= 0; state <= STATE_WRITE1; 
					ELSE				Count <= Count + 1; 
					END IF; 
				-----------------------------------
				-- Write command to DS18B20 : 0xCC, 0xBE 
				WHEN STATE_WRITE1 => 
					IF( Count>14 ) THEN Count <= 0; state <= STATE_READ; 
					ELSE				Count <= Count + 1; 
					END IF; 
				-----------------------------------
				-- Read the temperature from DS18B20 
				WHEN STATE_READ => 
					IF( Count>14 ) THEN Count <= 0; state <= STATE_RST2; 
					ELSE				Count <= Count + 1; 
					END IF; 
				-----------------------------------
				-- Interval power 
				
				-----------------------------------
				-----------------------------------
				-- Start the converter for the next turn 
				WHEN STATE_RST2 => 
					IF( Count>20 ) THEN Count <= 0; state <= STATE_WRITE2; 
					ELSE				Count <= Count + 1; 
					END IF; 
				-----------------------------------
				-- Write command to DS18B20 : 0xCC, 0x44 
				WHEN STATE_WRITE2 => 
					IF( Count>14 ) THEN Count <= 0; state <= STATE_WAIT; 
					ELSE				Count <= Count + 1; 
					END IF; 
				-----------------------------------
				-----------------------------------
				-- Wait for the next turn ... ( Update rate : 1S ) 
				WHEN STATE_WAIT => 
					Count <= 0; 
					
					IF( Fresh='0' ) THEN state <= STATE_RST1; 
					END IF; 
				-----------------------------------
				WHEN OTHERS => Count <= 0; 
			END CASE; 
		END IF; 
	END PROCESS; 
	
	--==============================================
	------------------------------------------------
	-- End of getting temperature 
	PROCESS( state, Count, CLKwrite0, CLKwrite1 )	
	BEGIN
		CASE state IS 
			-----------------------------------
			-- RESET 
			WHEN STATE_RST1 => 
				-- RESET PLUS 
				IF( Count<11 ) THEN VALUE <= '0';	-- 0 
				ELSE				VALUE <= '1';	-- 1 
				END IF; 
			-----------------------------------
			-- Write command to DS18B20 : 0xCC, 0xBE 
			WHEN STATE_WRITE1 => 
				IF( COMMAND1(Count)='0' ) THEN 	VALUE <= CLKwrite0;
				ELSE							VALUE <= CLKwrite1;
				END IF; 
			-----------------------------------
			-- Read the temperature from DS18B20 
			WHEN STATE_READ => 
				VALUE <= CLKwrite1;
			-----------------------------------
			-- Interval power 
				
			-----------------------------------
			-----------------------------------
			-- RESET 
			WHEN STATE_RST2 => 
				-- RESET PLUS 
				IF( Count<11 ) THEN VALUE <= '0';	-- 0 
				ELSE				VALUE <= '1';	-- 1 
				END IF; 
			-----------------------------------
			-- Write command to DS18B20 : 0xCC, 0xBE 
			WHEN STATE_WRITE2 => 
				IF( COMMAND2(Count)='0' ) THEN 	VALUE <= CLKwrite0;
				ELSE							VALUE <= CLKwrite1;
				END IF; 
			-----------------------------------
			WHEN OTHERS => VALUE <= '1'; 
		END CASE; 
	END PROCESS; 
	
	--==============================================
	------------------------------------------------
	-- Getting the temperature 
	-- Read datum from DS18B20 
	PROCESS( RESET, DQ, VALUE, state, Count, CLKread, EOCtemp )
		VARIABLE Receive : STD_LOGIC; 
	BEGIN 
		IF( RESET='0' ) THEN 
			DATA <= "0000000000000000";
		ELSIF( state=STATE_READ ) THEN 
			IF( CLKread'EVENT AND CLKread='1' ) THEN 
				IF( Receive='0' ) THEN 	DATA(Count) <= '0';
				ELSE					DATA(Count) <= '1';
				END IF; 
			END IF; 
			EOCtemp <= '0';
		ELSE
			EOCtemp <= '1';
		END IF; 
		
		-----------------------------------------------
		IF( VALUE='0' ) THEN DQ <= '0'; Receive := '1'; -- Output 
		ELSE				 DQ <= 'Z'; Receive := DQ; 	-- Input 
		END IF;
		
		
	END PROCESS; 
	
	--==============================================
	------------------------------------------------
	-- End of getting temperature 
	PROCESS( RESET, EOCtemp, DATA )
		VARIABLE FIGURE : INTEGER RANGE 0 TO 255; 
		VARIABLE VLOW, VHIGH : INTEGER RANGE 0 TO 15; 
	BEGIN
		IF( RESET='0' ) THEN 
			PDATA <= "00000000";
		ELSIF( EOCtemp'EVENT AND EOCtemp='1' ) THEN 
			-- BCD Code 
			PDATA <= CONV_STD_LOGIC_VECTOR(VHIGH, 4) & CONV_STD_LOGIC_VECTOR(VLOW, 4); 
			-- HEX Code 
		--	PDATA <= CONV_STD_LOGIC_VECTOR(FIGURE, 8);
		END IF; 
		
		FIGURE := CONV_INTEGER( DATA(11 DOWNTO 4) ); 
		
		-- HEX TO BCD 
		VHIGH := FIGURE /   10; 
		VLOW  := FIGURE REM 10; 
		
		EOC <= EOCtemp; 
		
	END PROCESS; 
	-------------------------------------------------
	-------------------------------------------------
	
END Behavioral;