assign lcd_rw = 1\'b0; //没有读操作,R/W信号始终为低电平
assign lcd_en = clk_div; //E信号出现高电平以及下降沿的时刻与LCD时钟相同
//时钟分频
always@(posedge sys_clk or negedge sys_rstn)
begin
if(!sys_rstn)
begin
delay_cnt<=18\'d0;
clk_div<=1\'b0;
end
else if(delay_cnt==18\'d249999)
begin
delay_cnt<=18\'d0;
clk_div<=~clk_div;
end
else
begin
delay_cnt<=delay_cnt+1\'b1;
clk_div<=clk_div;
end
end
always@(posedge clk_div or negedge sys_rstn) //State Machine
begin
if(!sys_rstn)
begin
state <= idle;
lcd_data <= 8\'bzzzzzzzz;
char_cnt <= 5\'d0;
end
else
begin
case(state)
idle: begin //初始状态
state <= clear;
lcd_data <= 8\'bzzzzzzzz;
end
clear: begin //清屏
state <= set_function;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00000001;
end
set_function: //功能设置(38H):8位数据接口/2行显示/5*8点阵字符
begin
state <= switch_mode;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00111000;
end
switch_mode: //显示开关控制(0CH):开显示,光标和闪烁关闭
begin
state <= set_mode;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00001100;
end
set_mode:begin //输入方式设置(06H):数据读写操作后,地址自动加一/画面不动
state <= shift;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00000110;
end
shift: begin //光标、画面位移设置(10H):光标向左平移一个字符位(光标显示是关闭的,所以实际上设置是看不出效果的)
state <= set_ddram1;
lcd_rs<=1\'b0;
lcd_data <= 8\'b0001_0000;
end
set_ddram1: //设置DDRAM的地址:第一行起始为00H(注意输出时DB7一定要为1)
begin
state <= write_ram1;
lcd_rs<=1\'b0;
lcd_data <= 8\'b1000_0000;//Line1
end
set_ddram2: //设置DDRAM的地址:第二行为40H(注意输出时DB7一定要为1)
begin
state <= write_ram2;
lcd_rs<=1\'b0;
lcd_data <= 8\'b1100_0000;//Line2
end
write_ram1:
begin
if(char_cnt <=5\'d10)
begin
char_cnt <= char_cnt + 1\'b1;
lcd_rs<=1\'b1;
lcd_data <= data_disp;
state <= write_ram1;
end
else
begin
state <= set_ddram2;
end
end
write_ram2:
begin
if(char_cnt <=5\'d26)
begin
char_cnt <= char_cnt + 1\'b1;
lcd_rs<=1\'b1;
lcd_data <= data_disp;
state <= write_ram2;
end
else
begin
char_cnt <=5\'d0;
state <= shift;
end
end
default: state <= idle;
endcase
end
end
assign lcd_rw = 1\'b0; //没有读操作,R/W信号始终为低电平
assign lcd_en = clk_div; //E信号出现高电平以及下降沿的时刻与LCD时钟相同
//时钟分频
always@(posedge sys_clk or negedge sys_rstn)
begin
if(!sys_rstn)
begin
delay_cnt<=18\'d0;
clk_div<=1\'b0;
end
else if(delay_cnt==18\'d249999)
begin
delay_cnt<=18\'d0;
clk_div<=~clk_div;
end
else
begin
delay_cnt<=delay_cnt+1\'b1;
clk_div<=clk_div;
end
end
always@(posedge clk_div or negedge sys_rstn) //State Machine
begin
if(!sys_rstn)
begin
state <= idle;
lcd_data <= 8\'bzzzzzzzz;
char_cnt <= 5\'d0;
end
else
begin
case(state)
idle: begin //初始状态
state <= clear;
lcd_data <= 8\'bzzzzzzzz;
end
clear: begin //清屏
state <= set_function;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00000001;
end
set_function: //功能设置(38H):8位数据接口/2行显示/5*8点阵字符
begin
state <= switch_mode;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00111000;
end
switch_mode: //显示开关控制(0CH):开显示,光标和闪烁关闭
begin
state <= set_mode;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00001100;
end
set_mode:begin //输入方式设置(06H):数据读写操作后,地址自动加一/画面不动
state <= shift;
lcd_rs<=1\'b0;
lcd_data <= 8\'b00000110;
end
shift: begin //光标、画面位移设置(10H):光标向左平移一个字符位(光标显示是关闭的,所以实际上设置是看不出效果的)
state <= set_ddram1;
lcd_rs<=1\'b0;
lcd_data <= 8\'b0001_0000;
end
set_ddram1: //设置DDRAM的地址:第一行起始为00H(注意输出时DB7一定要为1)
begin
state <= write_ram1;
lcd_rs<=1\'b0;
lcd_data <= 8\'b1000_0000;//Line1
end
set_ddram2: //设置DDRAM的地址:第二行为40H(注意输出时DB7一定要为1)
begin
state <= write_ram2;
lcd_rs<=1\'b0;
lcd_data <= 8\'b1100_0000;//Line2
end
write_ram1:
begin
if(char_cnt <=5\'d10)
begin
char_cnt <= char_cnt + 1\'b1;
lcd_rs<=1\'b1;
lcd_data <= data_disp;
state <= write_ram1;
end
else
begin
state <= set_ddram2;
end
end
write_ram2:
begin
if(char_cnt <=5\'d26)
begin
char_cnt <= char_cnt + 1\'b1;
lcd_rs<=1\'b1;
lcd_data <= data_disp;
state <= write_ram2;
end
else
begin
char_cnt <=5\'d0;
state <= shift;
end
end
default: state <= idle;
endcase
end
end