box.vhd

用vhdl语言编写的基于FPGA的波形发生器。对于做实验需要产生的波形非常有用。

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY BOX IS
	PORT( CLK :IN STD_LOGIC;
		  RES :IN STD_LOGIC;
		  DOUT: OUT STD_LOGIC_VECTOR ( 7 DOWNTO 0 );
		  DS0 : IN STD_LOGIC;
		  LCD_RS, LCD_E		: OUT	STD_LOGIC;
		  LCD_RW			: BUFFER STD_LOGIC;
		  DATA_BUS			: INOUT	STD_LOGIC_VECTOR(7 DOWNTO 0);
		  DS1 : IN STD_LOGIC	);
END;

ARCHITECTURE DACC OF BOX IS
COMPONENT allwave
	PORT (address : IN STD_LOGIC_VECTOR ( 7 DOWNTO 0 );
		  inclock : IN STD_LOGIC;--地址锁存器
		  q       : OUT STD_LOGIC_VECTOR (7 DOWNTO 0)
		  );
END COMPONENT;

COMPONENT PLLU
	PORT
	(
		areset		: IN STD_LOGIC  := '0';
		inclk0		: IN STD_LOGIC  := '0';
		c0		    : OUT STD_LOGIC 
	);
END COMPONENT;


	TYPE STATE_TYPE IS (HOLD, FUNC_SET, DISPLAY_ON, MODE_SET, 
	WRITE_CHAR1,WRITE_CHAR2,WRITE_CHAR3,
	WRITE1_CHAR1,WRITE1_CHAR2,WRITE1_CHAR3,
	WRITE2_CHAR1,WRITE2_CHAR2,WRITE2_CHAR3,
	WRITE3_CHAR1,WRITE3_CHAR2,WRITE3_CHAR3,
	DISPLAY_SET,
	WRITE_CHAR4,WRITE_CHAR5,WRITE_CHAR6,WRITE_CHAR7,
	RETURN_HOME, TOGGLE_E, RESET1, RESET2, 
	RESET3, DISPLAY_OFF, DISPLAY_CLEAR);
	
	SIGNAL state, next_command: STATE_TYPE;
	SIGNAL DATA_BUS_VALUE: STD_LOGIC_VECTOR(7 DOWNTO 0);
	SIGNAL CLK_COUNT_400HZ: STD_LOGIC_VECTOR(19 DOWNTO 0);
	SIGNAL CLK_400HZ : STD_LOGIC;
	
	SIGNAL Q1 : STD_LOGIC_VECTOR ( 7 DOWNTO 0 );
	SIGNAL CC : STD_LOGIC;
	
	BEGIN
	DATA_BUS <= DATA_BUS_VALUE WHEN LCD_RW = '0' ELSE "ZZZZZZZZ";
	
	PROCESS
	BEGIN
	 WAIT UNTIL CLK'EVENT AND CLK = '1';
		IF RES = '1' THEN
		 CLK_COUNT_400HZ <= X"00000";
		 CLK_400HZ <= '0';
		ELSE
				IF CLK_COUNT_400HZ < X"0EA60" THEN 
				 CLK_COUNT_400HZ <= CLK_COUNT_400HZ + 1;
				ELSE
		    	 CLK_COUNT_400HZ <= X"00000";
				 CLK_400HZ <= NOT CLK_400HZ;
				END IF;
		END IF;
	END PROCESS;
	
		PROCESS (CLK_400HZ, RES)
	BEGIN
		IF RES = '1' THEN
			state <= RESET1;
			DATA_BUS_VALUE <= X"38";
			next_command <= RESET2;
			LCD_E <= '1';
			LCD_RS <= '0';
			LCD_RW <= '0';

	ELSIF CLK_400HZ'EVENT AND CLK_400HZ = '1' THEN
-- GENERATE 1 SEC CLOCK SIGNAL FOR SECOND COUNT PROCESS

-- SEND TIME TO LCD		
	
			CASE state IS
-- Set Function to 8-bit transfer and 2 line display with 5x8 Font size
-- see Hitachi HD44780 family data sheet for LCD command and timing details
				WHEN RESET1 =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"38";
						state <= TOGGLE_E;
						next_command <= RESET2;
				WHEN RESET2 =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"38";
						state <= TOGGLE_E;
						next_command <= RESET3;
				WHEN RESET3 =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"38";
						state <= TOGGLE_E;
						next_command <= FUNC_SET;
-- EXTRA STATES ABOVE ARE NEEDED FOR RELIABLE PUSHBUTTON RESET OF LCD
				WHEN FUNC_SET =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"38";
						state <= TOGGLE_E;
						next_command <= DISPLAY_OFF;
-- Turn off Display and Turn off cursor
				WHEN DISPLAY_OFF =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"08";
						state <= TOGGLE_E;
						next_command <= DISPLAY_CLEAR;
-- Turn on Display and Turn off cursor
				WHEN DISPLAY_CLEAR =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"01";
						state <= TOGGLE_E;
						next_command <= DISPLAY_ON;
-- Turn on Display and Turn off cursor
				WHEN DISPLAY_ON =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"0C";
						state <= TOGGLE_E;
						next_command <= MODE_SET;
-- Set write mode to auto increment address and move cursor to the right
				WHEN MODE_SET =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"06";
						state <= TOGGLE_E;
						next_command <= DISPLAY_SET;


                WHEN DISPLAY_SET =>
					   IF DS0='0' AND DS1='0' THEN
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR1;
						END IF;
						
					   	IF DS0='1' AND DS1='0' THEN
					    state <= TOGGLE_E;
					    next_command <= WRITE1_CHAR1;
						END IF;
						
						IF DS0='0' AND DS1='1' THEN
					    state <= TOGGLE_E;
					    next_command <= WRITE2_CHAR1;
						END IF;
						
						IF DS0='1' AND DS1='1' THEN
					    state <= TOGGLE_E;
					    next_command <= WRITE3_CHAR1;
					   	END IF;
					
-- Write ASCII hex character in first LCD character location					
				WHEN WRITE_CHAR1 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"53";
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR2;
-- Write ASCII hex character in second LCD character location
				WHEN WRITE_CHAR2 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"49";
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR3;
-- Write ASCII hex character in third LCD character location
				WHEN WRITE_CHAR3 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"4E" ;
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR4;
-- Write ASCII hex character in first LCD character location


					
				WHEN WRITE1_CHAR1 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"4C";
						state <= TOGGLE_E;
						next_command <= WRITE1_CHAR2;
-- Write ASCII hex character in second LCD character location
				WHEN WRITE1_CHAR2 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"49";
						state <= TOGGLE_E;
						next_command <= WRITE1_CHAR3;
-- Write ASCII hex character in third LCD character location
				WHEN WRITE1_CHAR3 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"4E" ;
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR4;	
						
						
						
						
						
				WHEN WRITE2_CHAR1 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"54";
						state <= TOGGLE_E;
						next_command <= WRITE2_CHAR2;
-- Write ASCII hex character in second LCD character location
				WHEN WRITE2_CHAR2 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"52";
						state <= TOGGLE_E;
						next_command <= WRITE2_CHAR3;
-- Write ASCII hex character in third LCD character location
				WHEN WRITE2_CHAR3 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"49" ;
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR4;	
						
						
						
						
						
				WHEN WRITE3_CHAR1 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"53";
						state <= TOGGLE_E;
						next_command <= WRITE3_CHAR2;
-- Write ASCII hex character in second LCD character location
				WHEN WRITE3_CHAR2 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"51";
						state <= TOGGLE_E;
						next_command <= WRITE3_CHAR3;
-- Write ASCII hex character in third LCD character location
				WHEN WRITE3_CHAR3 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"55" ;
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR4;	
						
						
						
						
						
									
				
-- Write ASCII hex character in fourth LCD character location
				WHEN WRITE_CHAR4 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"20";
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR5;
-- Write ASCII hex character in fifth LCD character location
				WHEN WRITE_CHAR5 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"34";
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR6;
-- Write ASCII hex character in sixth LCD character location
				WHEN WRITE_CHAR6 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"38" ;
						state <= TOGGLE_E;
						next_command <= WRITE_CHAR7;
-- Write ASCII hex character in seventh LCD character location
				WHEN WRITE_CHAR7 =>
						LCD_E <= '1';
						LCD_RS <= '1';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"4D";
						state <= TOGGLE_E;
						next_command <= RETURN_HOME;

-- Return write address to first character postion
				WHEN RETURN_HOME =>
						LCD_E <= '1';
						LCD_RS <= '0';
						LCD_RW <= '0';
						DATA_BUS_VALUE <= X"80";
						state <= TOGGLE_E;
						next_command <= DISPLAY_SET;
-- The next two states occur at the end of each command to the LCD
-- Toggle E line - falling edge loads inst/data to LCD controller
				WHEN TOGGLE_E =>
						LCD_E <= '0';
						state <= HOLD;
-- Hold LCD inst/data valid after falling edge of E line				
				WHEN HOLD =>
						state <= next_command;
			END CASE;
		END IF;
	END PROCESS;
	
PROCESS ( CC )
	BEGIN
IF CC'EVENT AND CC = '1' THEN 

	IF DS0='0' AND DS1='0' THEN
		IF Q1<64 THEN

			Q1<=Q1+1; --Q1作为地址发生器计数器
		ELSE Q1<="00000000";
		END IF;
	END IF;
	
	IF DS0='1' AND DS1='0' THEN
		IF Q1<128 AND Q1>63 THEN
			Q1<=Q1+1;
		ELSE Q1<="01000000";
		END IF;
	END IF;
	
	IF DS0='0' AND DS1='1' THEN
		IF Q1<192 AND Q1>127 THEN
		 	Q1<=Q1+1;
		ELSE Q1<="10000000";
		END IF;
	END IF;
	
	IF DS0='1' AND DS1='1' THEN
		IF Q1<=255 AND Q1>191 THEN
			Q1<=Q1+1;
		ELSE Q1<="11000000";
		END IF;
	END IF;
	
END IF;
END PROCESS;

u1 : allwave PORT MAP( address=>Q1,q=> DOUT,inclock=>CC );
u2 : PLLU    PORT MAP( areset=>RES,inclk0=>CLK,c0=>CC );
END;