lcd.v.bak

基于FPGA的LCD1602显示

module lcd(clk,rst,lcd_e,lcd_rw,lcd_rs,data);
	input clk,rst;
	output lcd_e,lcd_rw,lcd_rs;
	output [7:0] data;
	reg lcd_rw,lcd_rs;
	reg [7:0] datain;
	reg [7:0] data;
	
	reg [10:0] state;
	reg flag;
	reg [5:0] address;
	reg [6:0] counter;
	reg [3:0] divcounter;
	reg       clk_int_r;
	reg       clk_int;	
	
	parameter IDLE		=11'b00000000000;
	parameter CLEAR		=11'b00000000001;		//清屏
	
	parameter RETURNCURSOR	=11'b00000000010;	//归home位
	
	parameter SETMODE	=11'b00000000100;		
	//输入方式设置，读写数据后ram地址增/减1；画面动/不动
	
	parameter SWITCHMODE	=11'b00000001000;	
	//显示状态设置，显示开/关；光标开/关；闪烁开/关
	
	parameter SHIFT		=11'b00000010000;		
	//光标画面滚动 画面/光标平移一位；左/右平移一位
	
	parameter SETFUNCTION	=11'b00000100000;	
	//工作方式设置 1：8/1：4位数据接口；两行/一行显示；5x10/5x7点阵
	
	parameter SETCGRAM	=11'b00001000000;		//设置CGRAM
	parameter SETDDRAM1	=11'b00010000000;		//设置DDRAM
	parameter SETDDRAM2	=11'b00011000000;		//设置DDRAM
	parameter READFLAG	=11'b00100000000;		//
	parameter WRITERAM	=11'b01000000000;		//写RAM
	parameter READRAM	=11'b10000000000;		//读RAM

	parameter cur_inc      	=1;
	parameter cur_dec      	=0;
	parameter cur_shift    	=1;
	parameter cur_noshift  	=0;
	parameter open_display 	=1;
	parameter open_cur     	=0;
	parameter blank_cur    	=0;
	parameter shift_display	=1;
	parameter shift_cur    	=0;
	parameter right_shift  	=1;
	parameter left_shift   	=0;
	parameter datawidth8   	=1;
	parameter datawidth4   	=0;
	parameter twoline      	=1;
	parameter oneline      	=0;
	parameter font5x10     	=1;
	parameter font5x7      	=0;
	

	
	

	
parameter CLK_FREQ = 'D50_000_000;//系统时钟50MHZ
parameter DCLK_FREQ = 'D50;//
	reg [20:0] div_reg;

always @(posedge clk or negedge rst)
    begin
      if(!rst)
        begin
          div_reg<=16'h00;  
          clk_int_r <= 1'b0; 
        end
      else if(div_reg < CLK_FREQ/DCLK_FREQ)  
            div_reg <= div_reg + 1'b1; 
           else
            begin
              div_reg<=21'h0;
              clk_int_r <= ~clk_int_r; 
            end
     end
		
always@(posedge clk or negedge rst)
if(!rst)
 clk_int <= 1'b0;
 else if(clk_int_r)
   	clk_int <= 	1'b1;
   	else
   	clk_int <= 1'b0;
		
assign lcd_e = clk_int;//下降沿lcd_e输出

		
		
always @ (posedge clk_int or negedge rst)
	 begin
		if(!rst)
		begin
			state<=IDLE;
			flag<=0;
			counter<=0;
			divcounter<=0;
			address<=0;
		end
		else
		begin
			//case(state)
			//IDLE		:begin 
				//			if(!flag)
					//		  begin
						//		state<=SETFUNCTION;
							//	flag<=1'b1;
								//counter<=0;
								//divcounter<=0;
						      //end
				            //else if(divcounter<4'd8)//改变移动速度
							  // begin
							    //divcounter<=divcounter+1;
							    //state<=IDLE;
						   	    //lcd_rw <=1'b1;
							   //end
							  //else
							   //begin
							    //divcounter<=0;
								//state<=SHIFT;
							   //end
						 //end
			//CLEAR			:begin lcd_rs<=0;lcd_rw<=0;data<=8'b0000_0001;
		//							state<=SETMODE;end   
			//SETMODE			:begin lcd_rs<=0;lcd_rw<=0;data[7:2]<=6'b000001;data[1]<=cur_inc;data[0]<=cur_noshift;
									//state<=SETDDRAM1;end
		//	RETURNCURSOR	:begin lcd_rs<=0;lcd_rw<=0;data<=8'b00000010;
									//state<=WRITERAM;end
			//SWITCHMODE 		:begin lcd_rs<=0;lcd_rw<=0;data[7:3]<=5'b00001;data[2]<=open_display;data[1]<=open_cur;data[0]<=blank_cur;
								//state<=CLEAR;end
			//SHIFT			:begin lcd_rs<=0;lcd_rw<=0;data[7:4]<=4'b0001;data[3]<=shift_display;data[2]<=left_shift;data[1:0]<=2'b00;
				//				state<=IDLE;end
			//SETFUNCTION		:begin lcd_rs<=0;lcd_rw<=0;data[7:5]<=3'b001;data[4]<=datawidth8;data[3]<=twoline;data[2]<=font5x10;data[1:0]<=2'b00;
								//state<=SWITCHMODE;end
			//SETCGRAM		:begin lcd_rs<=0;lcd_rw<=0;data<=8'b01000000;state<=IDLE;end
			//SETDDRAM1		:begin
			                  //lcd_rs<=0;
			                 // lcd_rw<=0;
			                 // state<=WRITERAM;
			                 //  if(counter==0)
			                  //   data<=8'b1000_0000;
			                  //  else
			                  //    data<=8'b1100_0000;
			                // end
			//SETDDRAM2		:begin lcd_rs<=0;lcd_rw<=0;data<=8'b10000000;state<=WRITERAM;end//0x80显示在第一行
			//WRITERAM		:begin
			                 // lcd_rs<=1;
			                 // lcd_rw<=0;
			                 // data<=datain;
			                 //  if(counter<7'd40)
			                  //   begin
                              //    address = counter+2;
                              //     counter=counter+2;
                               //    state<=WRITERAM;
                               //  end
                               //else  if(counter==7'd40)//1602lcd第一行能显示40个字符，可通过左移分别显示出来
			                   //   begin
			                   //    state<=SETDDRAM1;
			                    //    counter<=counter+1;
			                     // end
                                // else if(counter<7'd73)
                                //  begin
                               //   address=counter-'d41+'d8;//－41表示所有字符重新显示在第二行，从第8个字符开始显示
                                //   counter=counter+1;
                                //   state=WRITERAM;
                                 //  end
                                  // else if(counter<7'd81)
                                  //  begin
                                   //   address=counter-7'd81+7'd8;
                                    //  counter=counter+1;
                                     // state<=WRITERAM; 
                                    // end
                                  //else 
                                    //begin
                                     lcd_rs<=1;
                                     lcd_rw<=0;
                                      data<=8'd87;//"W"的ASCII值
                                      data<='w';
                                      state<=SHIFT;
                                   // end
                            // end                   
	     		//endcase
		end
	end
char_ram charram(.address(address),.data(datain));

endmodule