lcd1602如何自定义汉字（verilog）
今天一鼓作气，再研究了一下如何用LCD1602自定义汉字
1、用字模软件获取汉字所对应的数据（因为嫌麻烦所以直接用了网上一个帖子里有关“电”的数据，如下：04，1f,15,1f,15,15,1f,04,07）帖子链接：http://www.51hei.com/mcu/3696.html
2、主要知识点
（1）lcd1602的11个指令集与lcd1602的基本显示，前两篇文章已经详细说过，链接如下
http://www.cnblogs.com/aslmer/p/5801363.html
http://www.cnblogs.com/aslmer/p/5819422.html
（2）DDRAM 与 CGRAM 的区别，根据数据手册知道我们可以定义8个汉字，具体更多知识点请自己百度。
（3）主要的两个指令 Set CGRAM Address 、 Write data to RAM 。
3、在上篇文章的基础上修改代码如下：
难点就在状态机的控制，重点修改部分都用红色标注
module lcd_1602_driver( clk , rst_n , lcd_en , lcd_rw , lcd_rs , lcd_data ); input clk ; input rst_n ; output lcd_en ; output lcd_rw ; output lcd_rs ; output [7:0] lcd_data; wire clk ; wire rst_n ; wire lcd_en ; wire lcd_rw; reg [7:0] lcd_data; reg lcd_rs ; reg [7:0] c_state ; reg [7:0] n_state ; wire [127:0] row_1; wire write_flag; //wire [127:0] row_2; assign row_1 ="i am liu xiao yi" ; //assign row_2 ="happy everyday !"; //---------------------------------------------------------------------- //initialize //first step is waitng more than 20 ms. parameter TIME_20MS = 1000_000 ; //20000000/20=1000_000 //parameter TIME_15MS = 9'h100 ; //just for test parameter TIME_500HZ= 100_000 ; // //parameter TIME_500HZ= 4'hf; //just for test //use gray code 这里本来用的是格雷码，但是由于增添了两个状态，就随机写了f1,f2这两个数字。 parameter IDLE= 8'h00 ; parameter SET_FUNCTION= 8'h01 ; parameter DISP_OFF= 8'h03 ; parameter DISP_CLEAR= 8'h02 ; parameter ENTRY_MODE= 8'h06 ; parameter DISP_ON = 8'h07 ; parameter ROW1_ADDR= 8'h05 ; //----------------------修改1,增添这两个状态 parameter CGRAM_ADDR = 8'hf1; parameter CGRAM_DATA = 8'hf2; //----------------------- parameter ROW1_0= 8'h04 ; parameter ROW1_1= 8'h0C ; parameter ROW1_2= 8'h0D ; parameter ROW1_3= 8'h0F ; parameter ROW1_4= 8'h0E ; parameter ROW1_5= 8'h0A ; parameter ROW1_6= 8'h0B ; parameter ROW1_7= 8'h09 ; parameter ROW1_8= 8'h08 ; parameter ROW1_9= 8'h18 ; parameter ROW1_A= 8'h19 ; parameter ROW1_B= 8'h1B ; parameter ROW1_C= 8'h1A ; parameter ROW1_D= 8'h1E ; parameter ROW1_E= 8'h1F ; parameter ROW1_F= 8'h1D ; parameter ROW2_ADDR= 8'h1C ; parameter ROW2_0= 8'h14 ; parameter ROW2_1= 8'h15 ; parameter ROW2_2= 8'h17 ; parameter ROW2_3= 8'h16 ; parameter ROW2_4= 8'h12 ; parameter ROW2_5= 8'h13 ; parameter ROW2_6= 8'h11 ; parameter ROW2_7= 8'h10 ; parameter ROW2_8= 8'h30 ; parameter ROW2_9= 8'h31 ; parameter ROW2_A= 8'h33 ; parameter ROW2_B= 8'h32 ; parameter ROW2_C= 8'h36 ; parameter ROW2_D= 8'h37 ; parameter ROW2_E= 8'h35 ; parameter ROW2_F= 8'h34 ; reg [19:0] cnt_20ms ; always @(posedge clk or negedge rst_n)begin if(rst_n==1'b0)begin cnt_20ms<=0; end else if(cnt_20ms == TIME_20MS -1)begin cnt_20ms<=cnt_20ms; end else cnt_20ms<=cnt_20ms + 1 ; end wire delay_done = (cnt_20ms==TIME_20MS-1)? 1'b1 : 1'b0 ; //---------------------------------------------------------------------- //500ns lcd1602工作在500HZ,因此此处要分频 reg [19:0] cnt_500hz; always @(posedge clk or negedge rst_n)begin if(rst_n==1'b0)begin cnt_500hz <= 0; end else if(delay_done==1)begin if(cnt_500hz== TIME_500HZ - 1) cnt_500hz<=0; else cnt_500hz<=cnt_500hz + 1 ; end else cnt_500hz<=0; end assign lcd_en = (cnt_500hz>(TIME_500HZ-1)/2)? 1'b0 : 1'b1; //下降沿 assign write_flag = (cnt_500hz==TIME_500HZ - 1) ? 1'b1 : 1'b0 ; //set_function ,display off ，display clear ,entry mode set //---------------------------------------------------------------------- always @(posedge clk or negedge rst_n)begin if(rst_n==1'b0)begin c_state <= IDLE ; end else if(write_flag==1) begin c_state<= n_state ; end else c_state<=c_state ; end //-------------------------修改2 因为自定义一个汉字需要写8次地址并且给8次数据，所以用num和num1来控制。 reg [2:0]num,num1; always @(posedge clk or negedge rst_n)begin if(rst_n==1'b0)begin num<=0; end else if(c_state== CGRAM_ADDR&&write_flag) begin if(num==7) num<=0; else num<=num+8'b1; end else num<=num; end always @(posedge clk or negedge rst_n)begin if(rst_n==1'b0)begin num1<=0; end else if(c_state== CGRAM_DATA&&write_flag) begin if(num1==7) num1<=0; else num1<=num1+8'b1; end else num1<=num1; end //------------------------------------------------------------ always @(*)begin case (c_state) IDLE: n_state = SET_FUNCTION ; SET_FUNCTION: n_state = DISP_OFF ; DISP_OFF: n_state = DISP_CLEAR ; DISP_CLEAR: n_state = ENTRY_MODE ; ENTRY_MODE: n_state = DISP_ON ; DISP_ON : n_state = CGRAM_ADDR ; //------------------------------------------------ 修改3 当8个数据都写进相应地址里的时候，状态机才跳到ROW1_ADDR状态 CGRAM_ADDR: n_state = CGRAM_DATA ; // 8'hfe; CGRAM_DATA: if(num1==7) n_state = ROW1_ADDR; else n_state= CGRAM_ADDR; //------------------------------------------------ ROW1_ADDR: n_state = ROW1_0 ; ROW1_0: n_state = ROW1_1 ; ROW1_1: n_state = ROW1_2 ; ROW1_2: n_state = ROW1_3 ; ROW1_3: n_state = ROW1_4 ; ROW1_4: n_state = ROW1_5 ; ROW1_5: n_state = ROW1_6 ; ROW1_6: n_state = ROW1_7 ; ROW1_7: n_state = ROW1_8 ; ROW1_8: n_state = ROW1_9 ; ROW1_9: n_state = ROW1_A ; ROW1_A: n_state = ROW1_B ; ROW1_B: n_state = ROW1_C ; ROW1_C: n_state = ROW1_D ; ROW1_D: n_state = ROW1_E ; ROW1_E: n_state = ROW1_F ; ROW1_F: n_state = ROW2_ADDR ; ROW2_ADDR: n_state = ROW2_0 ; ROW2_0: n_state = ROW2_1 ; ROW2_1: n_state = ROW2_2 ; ROW2_2: n_state = ROW2_3 ; ROW2_3: n_state = ROW2_4 ; ROW2_4: n_state = ROW2_5 ; ROW2_5: n_state = ROW2_6 ; ROW2_6: n_state = ROW2_7 ; ROW2_7: n_state = ROW2_8 ; ROW2_8: n_state = ROW2_9 ; ROW2_9: n_state = ROW2_A ; ROW2_A: n_state = ROW2_B ; ROW2_B: n_state = ROW2_C ; ROW2_C: n_state = ROW2_D ; ROW2_D: n_state = ROW2_E ; ROW2_E: n_state = ROW2_F ; ROW2_F: n_state = ROW1_ADDR ; default: n_state = n_state ; endcase end assign lcd_rw = 0; always @(posedge clk or negedge rst_n)begin if(rst_n==1'b0)begin lcd_rs <= 0 ; //order or data 0: order 1:data end else if(write_flag == 1)begin if((n_state==SET_FUNCTION)||(n_state==DISP_OFF)|| (n_state==DISP_CLEAR)||(n_state==ENTRY_MODE)|| (n_state==DISP_ON ) ||(n_state==ROW1_ADDR)|| (n_state==ROW2_ADDR)||(n_state==CGRAM_ADDR))begin //修改4 lcd_rs<=0 ; end else begin lcd_rs<= 1; end end else begin lcd_rs<=lcd_rs; end end always @(posedge clk or negedge rst_n)begin if(rst_n==1'b0)begin lcd_data<=0 ; end else if(write_flag)begin case(n_state) IDLE: lcd_data <= 8'hxx; SET_FUNCTION: lcd_data <= 8'h38; //2*16 5*8 8位数据 DISP_OFF: lcd_data <= 8'h08; DISP_CLEAR: lcd_data <= 8'h01; ENTRY_MODE: lcd_data <= 8'h06; DISP_ON : lcd_data <= 8'h0c; //显示功能开，没有光标，且不闪烁， // ------------------------------------修改5 CGRAM_ADDR: begin case(num) 0: lcd_data <= 8'h40; 1: lcd_data <= 8'h41; 2: lcd_data <= 8'h42; 3: lcd_data <= 8'h43; 4: lcd_data <= 8'h44; 5: lcd_data <= 8'h45; 6: lcd_data <= 8'h46; 7: lcd_data <= 8'h47; endcase end CGRAM_DATA: begin case(num1) 0: lcd_data <= 8'h04; 1: lcd_data <= 8'h1f; 2: lcd_data <= 8'h15; 3: lcd_data <= 8'h1f; 4: lcd_data <= 8'h15; 5: lcd_data <= 8'h1f; 6: lcd_data <= 8'h04; 7: lcd_data <= 8'h07; endcase end //-------------------------------------修改6第一行显示 i am liu xiao yi 第二行全部显示汉字电 ROW1_ADDR: lcd_data <= 8'h80; //00+80 ROW1_0: lcd_data <= row_1 [127:120]; ROW1_1: lcd_data <= row_1 [119:112]; ROW1_2: lcd_data <= row_1 [111:104]; ROW1_3: lcd_data <= row_1 [103: 96]; ROW1_4: lcd_data <= row_1 [ 95: 88]; ROW1_5: lcd_data <= row_1 [ 87: 80]; ROW1_6: lcd_data <= row_1 [ 79: 72]; ROW1_7: lcd_data <= row_1 [ 71: 64]; ROW1_8: lcd_data <= row_1 [ 63: 56]; ROW1_9: lcd_data <= row_1 [ 55: 48]; ROW1_A: lcd_data <= row_1 [ 47: 40]; ROW1_B: lcd_data <= row_1 [ 39: 32]; ROW1_C: lcd_data <= row_1 [ 31: 24]; ROW1_D: lcd_data <= row_1 [ 23: 16]; ROW1_E: lcd_data <= row_1 [ 15: 8]; ROW1_F: lcd_data <= row_1 [ 7: 0]; ROW2_ADDR: lcd_data <= 8'hc0; //40+80 ROW2_0: lcd_data <=8'h00; //电 ROW2_1: lcd_data <=8'h00; ROW2_2: lcd_data <=8'h00; ROW2_3: lcd_data <=8'h00; ROW2_4: lcd_data <=8'h00; ROW2_5: lcd_data <=8'h00; ROW2_6: lcd_data <=8'h00; ROW2_7: lcd_data <=8'h00; ROW2_8: lcd_data <=8'h00; ROW2_9: lcd_data <=8'h00; ROW2_A: lcd_data <=8'h00; ROW2_B: lcd_data <=8'h00; ROW2_C: lcd_data <=8'h00; ROW2_D: lcd_data <=8'h00; ROW2_E: lcd_data <=8'h00; ROW2_F: lcd_data <=8'h00; endcase end else lcd_data<=lcd_data ; end endmodule
4、显示结果
