I've recently completed a project involving an LCD using this same
controller.  What I found is that with the 2 LCD's I was using for testing,
this initialization routine did not work.  What I found DID work was when I
left out
the first 3 'write4(3)' instructions.  Now, this goes against
everything I've read on the internet and from Hitachi's Datasheet.  I
only found 1 instance where someone used a different initialization
scheme and this seemed to work for me.

Was there anything wrong with what I was doing or do different LCD's behave
differently (even though they use the same controller)?

Here is my initialization routine:

void lcd_init(void)
{
LCD_EN_DIR = 0;                     //Set EN and RS lines to output;
LCD_RS_DIR = 0;

TRISBbits.TRISB0 = 0;             //Set data lines to output;
TRISBbits.TRISB1 = 0;
TRISBbits.TRISB2 = 0;
TRISBbits.TRISB3 = 0;

LCD_EN = 0;
LCD_RS = 0;                          //Write control bytes.
delay(1300000);

PORTB = 0x0002;                   //Set 4 bit mode.
LCD_STROBE();

lcd_write(0x28);                     //4 bit mode, 1/16 duty, 5x8 font.
lcd_write(0x08);                     //Display off.
lcd_write(0x0C);                    //Display on, cursor on.
lcd_write(0x06);                    //Entry mode.
}

Any insights?

-Tarun.

On 4/3/06, M. Adam Davis <stienman@gmail.com> wrote:
>
> What is your LCD init routine?  I've never experienced that problem
> with the cheap LCDs I have used with this routine:
>
> write4 just writes 4 bits to the LCD interface, write8 writes 8 bits
> in two cycles of 4 bits.  The rest should be pretty explanatory,
> except for the ??? which I sure could be determined from the data
> sheet in short order.
>
> void initlcd(void)
> {
>         delayms(20);    // Wait for LCD to power up ( >15ms )
>         RS=0;           // Set RS low for instruction
>         write4(3);      // Set interface to 8 bits
>         delayms(5);     // Wait for LCD execute instruction ( >4.1ms )
>         write4(3);      // Set interface to 8 bits
>         delayms(1);     // Wait for LCD execute instruction ( >100us )
>         write4(3);      // Set interface to 8 bits
>         delayms(5);     // Wait for LCD execute instruction (At this point
>                         // we could actually start using the busy flag)
>         write4(2);      // Set the display to 4 bit interface
>         delayms(5);     // Wait for LCD execute instruction
>         write8(0x28);   // Set the display to two line and ???
>         delayms(5);     // Wait for LCD execute instruction
>         write8(6);      // ???
>         delayms(5);     // Wait for LCD execute instruction
>         write8(1);      // Clear the LCD
>         delayms(5);     // Wait for LCD execute instruction
>         write8(0xf);    // ???
>         delayms(5);     // Wait for LCD execute instruction
>         return;
> }
>
> -Adam
>
> On 4/3/06, kravnus wolf <kravnus@yahoo.com> wrote:
> > I have written code for the LCD from bgmicro
> >
> >
> http://www.bgmicro.com/prodinfo.asp?sid=0968912037037037604814310&prodid=LCD1022&page=1&cri=lcd&stype=3
> >
> > I managed to get it started and printing characters on
> > it. What grips me is that if I reset the PIC through
> > MCLR quickly and numerous times the LCD just prints
> > blank! It seems that the LCD cannot handle quick
> > restart over and over again. I am left
> > clueless........
> >
> > Thanks,
> > John
> >
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--
Tarun Grover
Computer Engineering & Management V
McMaster University, Hamilton, ON, Canada
Chair, McMaster IEEE Student Branch Computer Chapter
grovert@mcmaster.ca - tarun.grover@gmail.com
tarun_grover@ieee.org - 905-518-2743
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