LCD1602驱动

谭力源 · 发表于 2016-5-17 19:15:06

新近写的，水平有限，欢迎拍砖。

实验程序：
---------------------------------------------------
module lcd1602_drive(
  input          clk,
  input          rst_n,
  // LCD1602 Interface
  output reg [7:0] lcd_data,
  output          lcd_e,
  output reg    lcd_rs,
  output          lcd_rw
);

// +++++++++++++++++++++++++++++++++++++
// 分频模块开始
// +++++++++++++++++++++++++++++++++++++
parameter CLK_DIV = 10_0000;          // 分频参数
reg [16:0] cnt;                      // 分频计数子
reg lcd_clk;                         // 500Hz

// 将50MHz板载时钟分频至500Hz
// 注：计数分频，非等占空比
always @(posedge clk, negedge rst_n)
begin
  if(!rst_n)
  begin cnt <= 1'b0; lcd_clk <= 0; end
  else
  begin
if(cnt <= CLK_DIV)
begin cnt <= cnt + 1'b1; lcd_clk <= 1; end
else
begin cnt <= 1'b0;    lcd_clk <= 0; end
  end
end
// -------------------------------------
// 分频模块结束
// -------------------------------------

// +++++++++++++++++++++++++++++++++++++
// LCD1602驱动模块开始
// +++++++++++++++++++++++++++++++++++++
/*
* 格雷码编码
* 状态数：初始化5个；换行1个；数据32个；空闲1个；共39个。
*/
// 初始化
parameter INIT_0  = 8'h00;
parameter INIT_1  = 8'h01;
parameter INIT_2  = 8'h03;
parameter INIT_3  = 8'h02;
parameter INIT_4  = 8'h06;
// 显示第一行
parameter ROW1_0  = 8'h07;
parameter ROW1_1  = 8'h05;
parameter ROW1_2  = 8'h04;
parameter ROW1_3  = 8'h0C;
parameter ROW1_4  = 8'h0D;
parameter ROW1_5  = 8'h0F;
parameter ROW1_6  = 8'h0E;
parameter ROW1_7  = 8'h0A;
parameter ROW1_8  = 8'h0B;
parameter ROW1_9  = 8'h09;
parameter ROW1_A  = 8'h08;
parameter ROW1_B  = 8'h18;
parameter ROW1_C  = 8'h19;
parameter ROW1_D  = 8'h1B;
parameter ROW1_E  = 8'h1A;
parameter ROW1_F  = 8'h1E;
// 换行
parameter CH_ROW  = 8'h1F;
// 显示第二行
parameter ROW2_0  = 8'h1D;
parameter ROW2_1  = 8'h1C;
parameter ROW2_2  = 8'h14;
parameter ROW2_3  = 8'h15;
parameter ROW2_4  = 8'h17;
parameter ROW2_5  = 8'h16;
parameter ROW2_6  = 8'h12;
parameter ROW2_7  = 8'h13;
parameter ROW2_8  = 8'h11;
parameter ROW2_9  = 8'h10;
parameter ROW2_A  = 8'h30;
parameter ROW2_B  = 8'h31;
parameter ROW2_C  = 8'h33;
parameter ROW2_D  = 8'h32;
parameter ROW2_E  = 8'h36;
parameter ROW2_F  = 8'h37;
// 空闲
parameter IDLE = 8'h35;

reg [5:0] current_state, next_state; // 现态、次态

// FSM: always1
always @ (posedge lcd_clk, negedge rst_n)
if(!rst_n)  current_state <= INIT_0;
else       current_state <= next_state;

// FSM: always2
always
begin
  case(current_state)
// 初始化
INIT_0  : next_state = INIT_1;
INIT_1  : next_state = INIT_2;
INIT_2  : next_state = INIT_3;
INIT_3  : next_state = INIT_4;
INIT_4  : next_state = ROW1_0;
// 显示第一行
ROW1_0  : next_state = ROW1_1;
ROW1_1  : next_state = ROW1_2;
ROW1_2  : next_state = ROW1_3;
ROW1_3  : next_state = ROW1_4;
ROW1_4  : next_state = ROW1_5;
ROW1_5  : next_state = ROW1_6;
ROW1_6  : next_state = ROW1_7;
ROW1_7  : next_state = ROW1_8;
ROW1_8  : next_state = ROW1_9;
ROW1_9  : next_state = ROW1_A;
ROW1_A  : next_state = ROW1_B;
ROW1_B  : next_state = ROW1_C;
ROW1_C  : next_state = ROW1_D;
ROW1_D  : next_state = ROW1_E;
ROW1_E  : next_state = ROW1_F;
ROW1_F  : next_state = CH_ROW;
// 换行
CH_ROW  : next_state = ROW2_0;
// 显示第二行
ROW2_0  : next_state = ROW2_1;
ROW2_1  : next_state = ROW2_2;
ROW2_2  : next_state = ROW2_3;
ROW2_3  : next_state = ROW2_4;
ROW2_4  : next_state = ROW2_5;
ROW2_5  : next_state = ROW2_6;
ROW2_6  : next_state = ROW2_7;
ROW2_7  : next_state = ROW2_8;
ROW2_8  : next_state = ROW2_9;
ROW2_9  : next_state = ROW2_A;
ROW2_A  : next_state = ROW2_B;
ROW2_B  : next_state = ROW2_C;
ROW2_C  : next_state = ROW2_D;
ROW2_D  : next_state = ROW2_E;
ROW2_E  : next_state = ROW2_F;
ROW2_F  : next_state = IDLE;
// 空闲
IDLE : next_state = IDLE;
default : next_state = INIT_0;
  endcase
end

// FSM: always3
always @ (posedge lcd_clk, negedge rst_n)
begin
  if(!rst_n)
  begin lcd_rs <= 0; lcd_data <= 8'h00; end
  else
  begin
case(current_state)
   INIT_0, CH_ROW, IDLE: lcd_rs <= 0;// 开始写指令
   ROW1_0, ROW2_0    : lcd_rs <= 1;// 开始写数据
endcase

case(current_state)
   // 写指令，初始化
   INIT_0  : lcd_data <= 8'h38;
   INIT_1  : lcd_data <= 8'h0C;
   INIT_2  : lcd_data <= 8'h01;
   INIT_3  : lcd_data <= 8'h06;
   INIT_4  : lcd_data <= 8'H80;
   // 写数据，显示第一行
   ROW1_0  : lcd_data <= "a";
   ROW1_1  : lcd_data <= "b";
   ROW1_2  : lcd_data <= "c";
   ROW1_3  : lcd_data <= "d";
   ROW1_4  : lcd_data <= "e";
   ROW1_5  : lcd_data <= "f";
   ROW1_6  : lcd_data <= "g";
   ROW1_7  : lcd_data <= "h";
   ROW1_8  : lcd_data <= "i";
   ROW1_9  : lcd_data <= "j";
   ROW1_A  : lcd_data <= "k";
   ROW1_B  : lcd_data <= "l";
   ROW1_C  : lcd_data <= "m";
   ROW1_D  : lcd_data <= "n";
   ROW1_E  : lcd_data <= "o";
   ROW1_F  : lcd_data <= "p";
   // 写指令，换行
   CH_ROW  : lcd_data <= 8'hC0;
   // 写数据，显示第二行
   ROW2_0  : lcd_data <= "A";
   ROW2_1  : lcd_data <= "B";
   ROW2_2  : lcd_data <= "C";
   ROW2_3  : lcd_data <= "D";
   ROW2_4  : lcd_data <= "E";
   ROW2_5  : lcd_data <= "F";
   ROW2_6  : lcd_data <= "G";
   ROW2_7  : lcd_data <= "H";
   ROW2_8  : lcd_data <= "I";
   ROW2_9  : lcd_data <= "J";
   ROW2_A  : lcd_data <= "K";
   ROW2_B  : lcd_data <= "L";
   ROW2_C  : lcd_data <= "M";
   ROW2_D  : lcd_data <= "N";
   ROW2_E  : lcd_data <= "O";
   ROW2_F  : lcd_data <= "P";
   // 写指令，空闲
   IDLE : lcd_data <= 8'h00;
endcase
  end
end

// 在时钟高电平有效，低电平失效
// 数据方可被锁存
assign lcd_e  = lcd_clk;
assign lcd_rw = 1'b0;                // 只写

// -------------------------------------
// LCD1602驱动模块结束
// -------------------------------------

endmodule
---------------------------------------------------

实验现象：

(原文件名:抓图-1.png)

Quartus II 综合报告：

(原文件名:抓图-2.png)

改进版测试文件

module lcd1602_test(
  input       CLOCK_50,             // 板载时钟50MHz
  input       Q_KEY,                // 板载按键RST
  // LCD1602 Interface
  output [7:0] LCD1602_DATA,          // LCD1602数据总线
  output    LCD1602_E,             // LCD1602使能
  output    LCD1602_RS,             // LCD1602指令数据选择
  output    LCD1602_RW             // LCD1602读写选择
);

// 0 ~ (8*16-1) = 128
// 16bits          -> 0123456789ABCDEF <-
wire [127:0] row1_val = "A Lcd Disp Test ";
wire [127:0] row2_val = "Amy-studio Pub  ";

// 例化LCD1602驱动
lcd1602_drive u0(
  .clk(CLOCK_50),
  .rst_n(Q_KEY),
  // LCD1602 Input Value
  .row1_val(row1_val),
  .row2_val(row2_val),
  // LCD1602 Interface
  .lcd_data(LCD1602_DATA),
  .lcd_e(LCD1602_E),
  .lcd_rs(LCD1602_RS),
  .lcd_rw(LCD1602_RW)
);

endmodule

完整代码（不晓得什么意思，ourdev一次能贴的代码太短）点击此处下载 ourdev_534318.zip(文件大小:125K) (原文件名:_10_lcd1602_test.zip)