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[/] [z80soc/] [tags/] [z80soc05/] [S3E/] [lcd.vhd] - Rev 40
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-- lcd.vhd -- Adapter by Ronivon C. costa - 2008/05/05 -- Added two more states to the state machines (one for each lcd line) -- Added RAM video (two ports) for the LCD -- Changed logic to read RAM/write to LCD in loop ----------------------------------------------------------- --Written by Rahul Vora --for the University of New Mexico --rhlvora@gmail.com library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; ---- Uncomment the following library declaration if instantiating ---- any Xilinx primitives in this code. --library UNISIM; --use UNISIM.VComponents.all; entity lcd is port( clk, reset : in std_logic; SF_D : out std_logic_vector(3 downto 0); LCD_E, LCD_RS, LCD_RW, SF_CE0 : out std_logic; lcd_addr : out std_logic_vector(4 downto 0); lcd_char : in std_logic_vector(7 downto 0)); end lcd; architecture behavior of lcd is type tx_sequence is (high_setup, high_hold, oneus, low_setup, low_hold, fortyus, done); signal tx_state : tx_sequence := done; signal tx_byte : std_logic_vector(7 downto 0); signal tx_init : bit := '0'; type init_sequence is (idle, fifteenms, one, two, three, four, five, six, seven, eight, done); signal init_state : init_sequence := idle; signal init_init, init_done : bit := '0'; signal i : integer range 0 to 750000 := 0; signal i2 : integer range 0 to 2000 := 0; signal i3 : integer range 0 to 82000 := 0; signal SF_D0, SF_D1 : std_logic_vector(3 downto 0); signal LCD_E0, LCD_E1 : std_logic; signal mux : std_logic; type display_state is (init, function_set, entry_set, set_display, clr_display, pause, set_addr0, set_addr1, char_print0, char_print1, done); signal cur_state : display_state := init; signal lcd_addr_sig : std_logic_vector(4 downto 0); begin lcd_addr <= lcd_addr_sig; SF_CE0 <= '1'; --disable intel strataflash LCD_RW <= '0'; --write only --The following "with" statements simplify the process of adding and removing states. --when to transmit a command/data and when not to with cur_state select tx_init <= '0' when init | pause | done, '1' when others; --control the bus with cur_state select mux <= '1' when init, '0' when others; --control the initialization sequence with cur_state select init_init <= '1' when init, '0' when others; --register select with cur_state select LCD_RS <= '0' when function_set|entry_set|set_display|clr_display|set_addr0|set_addr1, '1' when others; --what byte to transmit to lcd --refer to datasheet for an explanation of these values with cur_state select tx_byte <= "00101000" when function_set, "00000110" when entry_set, "00001100" when set_display, "00000001" when clr_display, "10000000" when set_addr0, "11000000" when set_addr1, lcd_char when char_print0|char_print1, "00000000" when others; --main state machine display: process(clk, reset) begin if(reset='1') then cur_state <= function_set; elsif(clk='1' and clk'event) then case cur_state is --refer to intialize state machine below when init => if(init_done = '1') then cur_state <= function_set; else cur_state <= init; end if; --every other state but pause uses the transmit state machine when function_set => if(i2 = 2000) then cur_state <= entry_set; else cur_state <= function_set; end if; when entry_set => if(i2 = 2000) then cur_state <= set_display; else cur_state <= entry_set; end if; when set_display => if(i2 = 2000) then cur_state <= clr_display; else cur_state <= set_display; end if; when clr_display => i3 <= 0; if(i2 = 2000) then cur_state <= pause; else cur_state <= clr_display; end if; when pause => if(i3 = 82000) then cur_state <= set_addr0; i3 <= 0; else cur_state <= pause; i3 <= i3 + 1; end if; when set_addr0 => if(i2 = 2000) then cur_state <= char_print0; lcd_addr_sig <= "00000"; else cur_state <= set_addr0; end if; when set_addr1 => if(i2 = 2000) then cur_state <= char_print1; lcd_addr_sig <= "10000"; else cur_state <= set_addr1; end if; when char_print0 => if(i2 = 2000) then if lcd_addr_sig = "01111" then cur_state <= set_addr1; else cur_state <= char_print0; lcd_addr_sig <= lcd_addr_sig + 1; end if; else cur_state <= char_print0; end if; when char_print1 => if(i2 = 2000) then if lcd_addr_sig = "11111" then cur_state <= set_addr0; else cur_state <= char_print1; lcd_addr_sig <= lcd_addr_sig + 1; end if; else cur_state <= char_print1; end if; when done => cur_state <= done; end case; end if; end process display; with mux select SF_D <= SF_D0 when '0', --transmit SF_D1 when others; --initialize with mux select LCD_E <= LCD_E0 when '0', --transmit LCD_E1 when others; --initialize --specified by datasheet transmit : process(clk, reset, tx_init) begin if(reset='1') then tx_state <= done; elsif(clk='1' and clk'event) then case tx_state is when high_setup => --40ns LCD_E0 <= '0'; SF_D0 <= tx_byte(7 downto 4); if(i2 = 2) then tx_state <= high_hold; i2 <= 0; else tx_state <= high_setup; i2 <= i2 + 1; end if; when high_hold => --230ns LCD_E0 <= '1'; SF_D0 <= tx_byte(7 downto 4); if(i2 = 12) then tx_state <= oneus; i2 <= 0; else tx_state <= high_hold; i2 <= i2 + 1; end if; when oneus => LCD_E0 <= '0'; if(i2 = 50) then tx_state <= low_setup; i2 <= 0; else tx_state <= oneus; i2 <= i2 + 1; end if; when low_setup => LCD_E0 <= '0'; SF_D0 <= tx_byte(3 downto 0); if(i2 = 2) then tx_state <= low_hold; i2 <= 0; else tx_state <= low_setup; i2 <= i2 + 1; end if; when low_hold => LCD_E0 <= '1'; SF_D0 <= tx_byte(3 downto 0); if(i2 = 12) then tx_state <= fortyus; i2 <= 0; else tx_state <= low_hold; i2 <= i2 + 1; end if; when fortyus => LCD_E0 <= '0'; if(i2 = 2000) then tx_state <= done; i2 <= 0; else tx_state <= fortyus; i2 <= i2 + 1; end if; when done => LCD_E0 <= '0'; if(tx_init = '1') then tx_state <= high_setup; i2 <= 0; else tx_state <= done; i2 <= 0; end if; end case; end if; end process transmit; --specified by datasheet power_on_initialize: process(clk, reset, init_init) --power on initialization sequence begin if(reset='1') then init_state <= idle; init_done <= '0'; elsif(clk='1' and clk'event) then case init_state is when idle => init_done <= '0'; if(init_init = '1') then init_state <= fifteenms; i <= 0; else init_state <= idle; i <= i + 1; end if; when fifteenms => init_done <= '0'; if(i = 750000) then init_state <= one; i <= 0; else init_state <= fifteenms; i <= i + 1; end if; when one => SF_D1 <= "0011"; LCD_E1 <= '1'; init_done <= '0'; if(i = 11) then init_state<=two; i <= 0; else init_state<=one; i <= i + 1; end if; when two => LCD_E1 <= '0'; init_done <= '0'; if(i = 205000) then init_state<=three; i <= 0; else init_state<=two; i <= i + 1; end if; when three => SF_D1 <= "0011"; LCD_E1 <= '1'; init_done <= '0'; if(i = 11) then init_state<=four; i <= 0; else init_state<=three; i <= i + 1; end if; when four => LCD_E1 <= '0'; init_done <= '0'; if(i = 5000) then init_state<=five; i <= 0; else init_state<=four; i <= i + 1; end if; when five => SF_D1 <= "0011"; LCD_E1 <= '1'; init_done <= '0'; if(i = 11) then init_state<=six; i <= 0; else init_state<=five; i <= i + 1; end if; when six => LCD_E1 <= '0'; init_done <= '0'; if(i = 2000) then init_state<=seven; i <= 0; else init_state<=six; i <= i + 1; end if; when seven => SF_D1 <= "0010"; LCD_E1 <= '1'; init_done <= '0'; if(i = 11) then init_state<=eight; i <= 0; else init_state<=seven; i <= i + 1; end if; when eight => LCD_E1 <= '0'; init_done <= '0'; if(i = 2000) then init_state<=done; i <= 0; else init_state<=eight; i <= i + 1; end if; when done => init_state <= done; init_done <= '1'; end case; end if; end process power_on_initialize; end behavior;
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