lcd_control_rtl_v3.vhd

LCD display driver for xilinx fpga

		   state_lcd <= init19;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init19 => -- wait for 1 祍

		 if(count = (t_pulse_c + t_upper_lower_c)) then

		   lcd_data  <= set_ddram_address_c2(3 downto 0);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init20;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init20 => -- wait for 40 祍

		 if(count = (t_pulse_c + t_next_pulse_c)) then

		   lcd_data  <= data_3_c(7 downto 4);

                   lcd_rw    <= '0';
		   
                   lcd_rs    <= '1';
		   
		   state_lcd <= init21;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init21 => -- wait for 1 祍

		 if(count = (t_pulse_c + t_upper_lower_c)) then

		   lcd_data  <= data_3_c(3 downto 0);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init22;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init22 => -- wait for 40 祍

		 if(count = (t_pulse_c + t_next_pulse_c)) then

		   lcd_data  <= data_4_c(7 downto 4);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init23;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init23 => -- wait for 1 祍

		 if(count = (t_pulse_c + t_upper_lower_c)) then

		   lcd_data  <= data_4_c(3 downto 0);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init24;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;
		 
	       when init24 => -- wait for 40 祍

		 if(count = (t_pulse_c + t_next_pulse_c)) then

		   lcd_data  <= data_5_c(7 downto 4);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init25;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init25 => -- wait for 1 祍

		 if(count = (t_pulse_c + t_upper_lower_c)) then

		   lcd_data  <= data_5_c(3 downto 0);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init26;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;
		 
	       when init26 => -- wait for 40 祍

		 if(count = (t_pulse_c + t_next_pulse_c)) then

		   lcd_data  <= data_6_c(7 downto 4);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init27;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init27 => -- wait for 1 祍

		 if(count = (t_pulse_c + t_upper_lower_c)) then

		   lcd_data  <= data_6_c(3 downto 0);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init28;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;
		 
	       when init28 => -- wait for 40 祍

		 if(count = (t_pulse_c + t_next_pulse_c)) then

		   lcd_data  <= data_7_c(7 downto 4);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init29;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;

	       when init29 => -- wait for 1 祍

		 if(count = (t_pulse_c + t_upper_lower_c)) then

		   lcd_data  <= data_7_c(3 downto 0);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init30;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;
		 		 
	       when init30 => -- wait for 40 祍

		 if(count = (t_pulse_c + t_next_pulse_c)) then

		   lcd_data  <= data_8_c(7 downto 4);

                   lcd_rw    <= '0';
		   
		   state_lcd <= init31;

		   count     <= 0;
		   
		 elsif (count = t_pulse_c) then
		   
                   lcd_rw    <= '1';

   		   count     <= count + 1;
		   
		 elsif (count = (t_pulse_c - t_hold_c)) then

		   lcd_e     <= '0';		   

		   count     <= count + 1;
		   
		 elsif (count = t_setup_c) then

		   lcd_e     <= '1';   

		   count     <= count + 1;
		   
		 else

		   count     <= count + 1;

		 end if;
		 
	       when init31  => null; -- wait for 1 祍

	       when others =>

		 state_lcd  <= lcdreset;

	     end case;

	  end if;
			
	end process;
	
 end rtl;