Download: design files
This lab writes two lines to the LCD.
The top-level module must link to the following pins:
// LCD Module 16X2 output LCD_ON, // LCD Power ON/OFF output LCD_BLON, // LCD Back Light ON/OFF output LCD_RW, // LCD Read/Write Select, 0 = Write, 1 = Read output LCD_EN, // LCD Enable output LCD_RS, // LCD Command/Data Select, 0 = Command, 1 = Data inout [7:0] LCD_DATA // LCD Data bus 8 bits );
A reset delay gives some time for peripherals to initialize
wire DLY_RST; Reset_Delay r0( .iCLK(CLOCK_50),.oRESET(DLY_RST) );
turn LCD ON
assign LCD_ON = 1'b1; assign LCD_BLON = 1'b1;
Instantiate the LCD_TEST module.
LCD_TEST u1( // Host Side .iCLK(CLOCK_50), .iRST_N(DLY_RST), // LCD Side .LCD_DATA(LCD_DATA), .LCD_RW(LCD_RW), .LCD_EN(LCD_EN), .LCD_RS(LCD_RS) );
module LCD_TEST (
// Host Side
input iCLK,iRST_N,
// LCD Side
output [7:0] LCD_DATA,
output LCD_RW,LCD_EN,LCD_RS
);
// Internal Wires/Registers
reg [5:0] LUT_INDEX;
reg [8:0] LUT_DATA;
reg [5:0] mLCD_ST;
reg [17:0] mDLY;
reg mLCD_Start;
reg [7:0] mLCD_DATA;
reg mLCD_RS;
wire mLCD_Done;
parameter LCD_INTIAL = 0;
parameter LCD_LINE1 = 5;
parameter LCD_CH_LINE = LCD_LINE1+16;
parameter LCD_LINE2 = LCD_LINE1+16+1;
parameter LUT_SIZE = LCD_LINE1+32+1;
always@(posedge iCLK or negedge iRST_N)
begin
if(!iRST_N)
begin
LUT_INDEX <= 0;
mLCD_ST <= 0;
mDLY <= 0;
mLCD_Start <= 0;
mLCD_DATA <= 0;
mLCD_RS <= 0;
end
else
begin
if(LUT_INDEX<LUT_SIZE)
begin
case(mLCD_ST)
0: begin
mLCD_DATA <= LUT_DATA[7:0];
mLCD_RS <= LUT_DATA[8];
mLCD_Start <= 1;
mLCD_ST <= 1;
end
1: begin
if(mLCD_Done)
begin
mLCD_Start <= 0;
mLCD_ST <= 2;
end
end
2: begin
if(mDLY<18'h3FFFE)
mDLY <= mDLY + 1'b1;
else
begin
mDLY <= 0;
mLCD_ST <= 3;
end
end
3: begin
LUT_INDEX <= LUT_INDEX + 1'b1;
mLCD_ST <= 0;
end
endcase
end
end
end
always
begin
case(LUT_INDEX)
// Initial
LCD_INTIAL+0: LUT_DATA <= 9'h038;
LCD_INTIAL+1: LUT_DATA <= 9'h00C;
LCD_INTIAL+2: LUT_DATA <= 9'h001;
LCD_INTIAL+3: LUT_DATA <= 9'h006;
LCD_INTIAL+4: LUT_DATA <= 9'h080;
// Line 1
LCD_LINE1+0: LUT_DATA <= 9'h141; // <Altera DE2 Kit>
LCD_LINE1+1: LUT_DATA <= 9'h16C;
LCD_LINE1+2: LUT_DATA <= 9'h174;
LCD_LINE1+3: LUT_DATA <= 9'h165;
LCD_LINE1+4: LUT_DATA <= 9'h172;
LCD_LINE1+5: LUT_DATA <= 9'h161;
LCD_LINE1+6: LUT_DATA <= 9'h120;
LCD_LINE1+7: LUT_DATA <= 9'h144;
LCD_LINE1+8: LUT_DATA <= 9'h145;
LCD_LINE1+9: LUT_DATA <= 9'h132;
LCD_LINE1+10: LUT_DATA <= 9'h120;
LCD_LINE1+11: LUT_DATA <= 9'h142;
LCD_LINE1+12: LUT_DATA <= 9'h16F;
LCD_LINE1+13: LUT_DATA <= 9'h161;
LCD_LINE1+14: LUT_DATA <= 9'h172;
LCD_LINE1+15: LUT_DATA <= 9'h164;
// Change Line
LCD_CH_LINE: LUT_DATA <= 9'h0C0;
// Line 2
LCD_LINE2+0: LUT_DATA <= 9'h14E; // Nice To See You!
LCD_LINE2+1: LUT_DATA <= 9'h169;
LCD_LINE2+2: LUT_DATA <= 9'h163;
LCD_LINE2+3: LUT_DATA <= 9'h165;
LCD_LINE2+4: LUT_DATA <= 9'h120;
LCD_LINE2+5: LUT_DATA <= 9'h154;
LCD_LINE2+6: LUT_DATA <= 9'h16F;
LCD_LINE2+7: LUT_DATA <= 9'h120;
LCD_LINE2+8: LUT_DATA <= 9'h153;
LCD_LINE2+9: LUT_DATA <= 9'h165;
LCD_LINE2+10: LUT_DATA <= 9'h165;
LCD_LINE2+11: LUT_DATA <= 9'h120;
LCD_LINE2+12: LUT_DATA <= 9'h159;
LCD_LINE2+13: LUT_DATA <= 9'h16F;
LCD_LINE2+14: LUT_DATA <= 9'h175;
LCD_LINE2+15: LUT_DATA <= 9'h121;
default: LUT_DATA <= 9'dx ;
endcase
end
LCD_Controller u0(
// Host Side
.iDATA(mLCD_DATA),
.iRS(mLCD_RS),
.iStart(mLCD_Start),
.oDone(mLCD_Done),
.iCLK(iCLK),
.iRST_N(iRST_N),
// LCD Interface
.LCD_DATA(LCD_DATA),
.LCD_RW(LCD_RW),
.LCD_EN(LCD_EN),
.LCD_RS(LCD_RS) );
endmodule
lcd_controller.v
module LCD_Controller (
// Host Side
input [7:0] iDATA,
input iRS,
input iStart,
output reg oDone,
input iCLK,iRST_N,
// LCD Interface
output [7:0] LCD_DATA,
output LCD_RW,
output reg LCD_EN,
output LCD_RS );
parameter CLK_Divide = 16;
// Internal Register
reg [4:0] Cont;
reg [1:0] ST;
reg preStart,mStart;
/////////////////////////////////////////////
// Only write to LCD, bypass iRS to LCD_RS
assign LCD_DATA = iDATA;
assign LCD_RW = 1'b0;
assign LCD_RS = iRS;
/////////////////////////////////////////////
always@(posedge iCLK or negedge iRST_N)
begin
if(!iRST_N)
begin
oDone <= 1'b0;
LCD_EN <= 1'b0;
preStart<= 1'b0;
mStart <= 1'b0;
Cont <= 0;
ST <= 0;
end
else
begin
////// Input Start Detect ///////
preStart<= iStart;
if({preStart,iStart}==2'b01)
begin
mStart <= 1'b1;
oDone <= 1'b0;
end
//////////////////////////////////
if(mStart)
begin
case(ST)
0: ST <= 1; // Wait Setup
1: begin
LCD_EN <= 1'b1;
ST <= 2;
end
2: begin
if(Cont<CLK_Divide)
Cont <= Cont + 1'b1;
else
ST <= 3;
end
3: begin
LCD_EN <= 1'b0;
mStart <= 1'b0;
oDone <= 1'b1;
Cont <= 0;
ST <= 0;
end
endcase
end
end
end
endmodule
reset_delay.vThis module holds reset low for awhile (about 220 / 50 MHz = 21 msec) to give internal circuits time to power up.
module Reset_Delay( input iCLK, output reg oRESET);
reg [19:0] Cont;
always@(posedge iCLK)
begin
if(Cont!=20'hFFFFF)
begin
Cont <= Cont + 1'b1;
oRESET <= 1'b0;
end
else
oRESET <= 1'b1;
end
endmodule
Maintained by John Loomis, last updated 20 January 2008