Thank you !
Adrresses- this is the only way to know the address?
The address not write in anywhere?

Thank you for help!!
-This is the first product that i connect to this project & this is the meaning to check I2C.
-addresses- which addresses? I know 0X50 or 80.
-What the problem with stop/start?

I have a Matrix-Orbital glk12232-25 connect to pic18f8720 .
Icannot to "speak" with my lcd.
this is my code:

void wait_end_procc(void){
while(SSPIF==0);
SSPIF=0;
}

void start_bit(void){
SSPIF=0;
SEN=1;
wait_end_procc();
}

void stop_bit(void){
SSPIF=0;
PEN=1;
wait_end_procc();
}

void ...