This might clarify my problem a bit. The way i wright data to it is through an interrupt. When a button on the keypad at adress 0c000 is pressed the program vectors to an interrupt, where it gets the data from it. The code is as follows:

void interrupt(void) interrupt 0
{
unsigned char x;
x=XBYTE[0x0c000];
if (x == 0x00)
{P1 = 0x31;
2LCD( );}
else if (x == 0x01)
{P1 = 0x32;
2LCD( );} etc.
}

void 2LCD(void)
{
P3_7 = 1; //e
P3_6 = 1; //rs
10usDelay( );
P3_7 = 0;
}

P1 is connected to the LCD.