cyclone III: LCD Help needed

Altera_Forum · ‎08-14-2009

I have been trying to program the lcd on the cyclone iii but i don;t get any respone...i even probed the pins to check if what the pins were what they should be and most of the data pins just stay on high.........The program i wrote is shown below: and i assign the pinouts according to the reference manual.....help is urgently needed............

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module lcd_display (clk,user_dipswitch2,user_dipswitch3,mydata,lcd_rs, lcd_rw, lcd_e, lcd_code);

input clk;

input user_dipswitch2;

input user_dipswitch3;

input [7:0] mydata;

integer count;

reg busy_flag;

//reg [6:0] lcd_code

output reg lcd_rs ;

output reg lcd_rw ;

output reg [7:0]lcd_code;

output reg lcd_e;

initial

begin

busy_flag <= lcd_code[7];

lcd_rs <= 0;

lcd_rw <= 0;

lcd_e <= 0;

count <= 0;

end

always @ (posedge clk )

begin

lcd_rs <= 0;

lcd_rw <= 1;

if (user_dipswitch2 && !busy_flag) //initialize lcd

begin

lcd_rs <= 0;

lcd_rw <= 0;

lcd_e <= 1;

case (count)

0: begin //function set

lcd_code <= 8'b00111100;

count <= 1;

end

1: begin // Display on

lcd_code <= 8'b00001111;

count <= 2;

end

2: begin // Display clear

lcd_code <= 8'b00000001;

count <= 3;

end

3: begin // Entry mode set

lcd_code <= 8'b00000111;

count <= 4;

end

4: lcd_e <= 0;

endcase

end

else if (!user_dipswitch2 && !busy_flag && user_dipswitch3)

begin

lcd_rs<= 1;

lcd_rw <= 0;

lcd_e <= 1;

lcd_code = 8'b11100011;

end

endmodule

Altera_Forum · ‎08-14-2009

This kind of LCD is extremely slow, what is your clock frequency?

commands like "clear screen", take to execute even 40 ms.

Did you simulate this module?

Altera_Forum · ‎08-15-2009

thanks for the reply....am fairly new to verilog...am not familliar about how to introduce the timing into the hardware......am using 50MHz