Extend Your Pi - Raspberry Pi Hacks - page 309

SPI.setBitOrder(MSBFIRST);
SPI.setDataMode(SPI_MODE0);
SPI.setClockDivider(SPI_CLOCK_DIV128);
initialise();
}
void loop(){
displayString(0,0,char1,16);
delay(2000);
clear();
displayString(1,0,char2,16);
displayString(2,0,char3,16);
delay(2000);
clear();
}
void initialise(){
pinMode(latchPin, OUTPUT);
digitalWrite(latchPin, LOW);
delayMicroseconds(80);
writeCommand(0x30);
writeCommand(0x0c);
writeCommand(0x01);
writeCommand(0x06);
}
void displayString(int X,int Y,unsigned char *ptr,int dat){
int i;
switch(X){
case 0: Y|=0x80;break;
case 1: Y|=0x90;break;
case 2: Y|=0x88;break;
case 3: Y|=0x98;break;
default: break;
}