I recently obtained some PDC1602M03 16x2 PLED displays from Farnell and some samples of the latest PDD2401M02 graphic modules courtesy of Craft Data UK. I've created an 8 bit interface set of functions in C in a demo program for the 16*2 displays and some demo code for the graphics displays.

The following functions are in the 1602 code:

void lcd_on(void);  //turn display on
void lcd_off(void);  //turn display off
void setRS(void); //set RS
void clrRS(void);  //clear RS
void setRW(void); //set RW
void clrRW(void); //clear RW
void setEN(void); //set EN
void clrEN(void); //clear EN
void lcd_command(unsigned char command); //send command to LCD
void lcd_putchar(unsigned char DD); //send character to LCD
void lcd_clear(void); //clear the display
void lcd_init(void); //initialize the display
void lcd_update (unsigned char *line1, unsigned char *line2); //Send 2 char arrays to LCD for lines 1 and 2 up to 40 bytes
void lcd_shiftdisplay(unsigned char direction); //shifts the display  ;  left=0, right=1
void lcd_shiftcursor(unsigned char direction); //shifts the cursor  ;  left=0, right=1
void lcd_cursor(unsigned char cursoron, unsigned char blinkon); off = 0 ; on=1
void lcd_userchars(unsigned char flash *userchar); // Expects 64 byte flash array defining 8 characters
void lcd_gotoxy(unsigned char x, unsigned char y); //Move cursor to position x, y

The 2401 code contains functions to update the screen and put characters and strings on the screen. I'll be creating a fuller set of functions when I get samples of the M03 version with an enhanced interface.

I've also written a windows program to create and modify ascii fonts for the graphics display module. The fonts are stored as binary files which can be edited and saved. The program creates the C code for a full 128 character font. Here's a sample font binary file.