/* HD44780 Library by Peter Fuhrmann

* this uses 4bit mode only for now.

* The Data Lines 7:4 shall be connected to the Display Port 3:0

*/

#include <avr/io.h>

#include <avr/pgmspace.h>

#include "hd44780.h"

//set this for 4bit mode

//The Data Lines 7:4 shall be connected to the Display Port 3:0 then

//#define IF4BIT

#if 0

#undef IF4BIT

#define PIN_RS PD5

#define PIN_E PD6

#define PIN_RW PD7

#define DISP_DDR_D DDRC

#define DISP_PORT_D PORTC

#define DISP_PIN PINC

#define DISP_DDR_C DDRD

#define DISP_PORT_C PORTD

#else

#define PIN_RS PD5

#define PIN_RW PD7

#define PIN_E PD6

//Port, to which the Datalines of the Display are connected

#define DISP_DDR_D DDRD

#define DISP_PORT_D PORTD

#define DISP_PIN PIND

//Port, to which the Control Lines of the Display are connected

#define DISP_DDR_C DDRD

#define DISP_PORT_C PORTD

#define DISP_LEN 16

#define DISP_LINES 2

#endif

/* Instructions */

#define CLEAR 0x01 /* no params */

#define HOME 0x02 /* no params */

#define ENTRY_MODE 0x04 /* B1 = cursor direction(1=right) B0 = do display shift */

#define ON_OFF 0x08 /* B2 = Display B1 = Cursor B0 = Blink */

#define SHIFT 0x10 /* B3 = Move Cursor(1)/ Shift Display(0) B2 = Shift Direction */

#define FUNCTION 0x20 /* B4 = Data Length (0=4, 1=8) B3 = Num of lines B2 = Font(0) */

#define SET_CGRAM 0x40 /* Character Generator Address */

#define SET_DDRAM 0x80 /* Character Address */

void wait50ms(){

uint16_t x; char y;

for (y=1;y<8;y++){

for (x=1;x<50000;x++){};

}

}

void wait200us(){

uint8_t x;

for (x=1;x<200;x++){};

}

void hd44780_send(uint8_t data){

uint8_t busy;

#ifdef IF4BIT

DISP_PORT_C |= _BV(PIN_E);

DISP_PORT_D &= 0xF0;

DISP_PORT_D |= ((data >> 4) & 0x0F);

DISP_PORT_C &= ~_BV(PIN_E);

DISP_PORT_C |= _BV(PIN_E);

DISP_PORT_D &= 0xF0;

DISP_PORT_D |= (data & 0x0F);

DISP_PORT_C &= ~_BV(PIN_E);

#else

DISP_PORT_C |= _BV(PIN_E);

DISP_PORT_D = (data);

DISP_PORT_C &= ~_BV(PIN_E);

#endif

#ifdef IF4BIT

DISP_DDR_D &= 0XF0; //Data lines 3:0 to Input

DISP_PORT_D |= 0x0F; //Pullups on on Data lines

#else

DISP_DDR_D = 0x00; //Data lines to Input

DISP_PORT_D = 0xFF; //Pullups on

#endif

DISP_PORT_C = (DISP_PORT_C | 1<<PIN_RW) & ~(1<<PIN_RS);

do{

DISP_PORT_C |= _BV(PIN_E);

asm volatile ("nop\n\tnop\n\t"::);

#ifdef IF4BIT

busy = (DISP_PIN & 0x08);

DISP_PORT_C &= ~_BV(PIN_E);

DISP_PORT_C |= _BV(PIN_E);

DISP_PORT_C &= ~_BV(PIN_E);

#else

busy = (DISP_PIN & 0x80);

DISP_PORT_C &= ~_BV(PIN_E);

#endif

}while(busy);

DISP_PORT_C &= ~(1<<PIN_RW | 1<<PIN_RS );

#ifdef IF4BIT

DISP_DDR_D |= 0x0F; //Data Lines to Output

#else

DISP_DDR_D = 0xFF;

#endif

}

// send Data to display without checking the Busy Flag, needed for iniializing Display

void hd44780_send_nobusy(uint8_t data){

#ifdef IF4BIT

DISP_PORT_C |= _BV(PIN_E);

DISP_PORT_D &= 0xF0;

DISP_PORT_D |= (data >> 4);

DISP_PORT_C &= ~_BV(PIN_E);

wait200us();

DISP_PORT_C |= _BV(PIN_E);

DISP_PORT_D &= 0xF0;

DISP_PORT_D |= (data & 0x0F);

DISP_PORT_C &= ~_BV(PIN_E);

wait200us();

#else

DISP_PORT_C |= _BV(PIN_E);

DISP_PORT_D = data;

DISP_PORT_C &= ~_BV(PIN_E);

wait200us();

#endif

}

/* reads and returns the address counter */

uint8_t hd44780_read(){

uint8_t address;

#ifdef IF4BIT

DISP_DDR_D &= 0xF0;

DISP_PORT_D |= 0x0F;

DISP_PORT_C &= ~(1<<PIN_RS);

DISP_PORT_C |= (1<<PIN_RW);

DISP_PORT_C |= 1<<PIN_E;

asm volatile ("nop\n\tnop\n\t"::);

address = DISP_PIN & 0x07; //dont read busy flag

DISP_PORT_C &= ~_BV(PIN_E);

address <<= 4;

DISP_PORT_C |= _BV(PIN_E);

asm volatile ("nop\n\tnop\n\t"::);

address |= DISP_PIN & 0x0F;

DISP_PORT_C &= ~_BV(PIN_E);

DISP_PORT_C &= ~(1<<PIN_RW);

DISP_DDR_D |= 0x0F;

#else

DISP_DDR_D = 0x00;

DISP_PORT_D = 0xFF;

DISP_PORT_C &= ~(1<<PIN_RS);

DISP_PORT_C |= (1<<PIN_RW);

DISP_PORT_C |= 1<<PIN_E;

asm volatile ("nop\n\tnop\n\t"::);

address = DISP_PIN & 0x7F; //dont read busy flag

DISP_PORT_C &= ~_BV(PIN_E);

DISP_PORT_C &= ~(1<<PIN_RW);

DISP_DDR_D = 0xFF;

#endif

return address;

}

void hd44780_command(uint8_t command){

DISP_PORT_C &= ~(1<<PIN_RS);

hd44780_send(command);

}

void hd44780_data(uint8_t data){

DISP_PORT_C |= 1<<PIN_RS;

hd44780_send(data);

}

/* init the controller and clear the Display */

void hd44780_init(){

#ifdef IF4BIT

DISP_DDR_D |= 0x0F;

DISP_PORT_D &= 0xF0;

#else

DISP_DDR_D = 0xFF;

DISP_PORT_D = 0x00;

#endif

DISP_DDR_C |= (1<<PIN_E|1<<PIN_RW|1<<PIN_RS);

DISP_PORT_C &= ~(1<<PIN_E|1<<PIN_RW|1<<PIN_RS);

wait50ms();

#ifdef IF4BIT

hd44780_send_nobusy(0x33);

hd44780_send_nobusy(0x32);// Put Display in 4bit mode

hd44780_send_nobusy(0x28);// Put Display in 4bit mode

hd44780_command(0x28);// 2 Lines 5x7 DOT

#else

hd44780_send_nobusy(0x30);

hd44780_send_nobusy(0x30);

hd44780_send_nobusy(0x30);

hd44780_send_nobusy(0x30);// Put Display in 8bit mode

hd44780_command(0x30);

hd44780_command(0x38);// 2 Lines 5x7 DOT

#endif

hd44780_command(0x10);// cursor move

hd44780_command(0x0F);//Display on, cursor on, cursor blink

hd44780_command(0x01);//clear Display

}

void hd44780_set_cursor(uint8_t row, uint8_t col){

hd44780_command(0x80|(uint8_t)(row<<6)|col);

}

void hd44780_backspace(uint8_t num){

uint8_t curs_pos = hd44780_read();

uint8_t x;

hd44780_command(SET_DDRAM|(curs_pos-num));

for(x=0;x<num;x++){

hd44780_data(' ');

}

hd44780_command(SET_DDRAM|(curs_pos-1));

}

void hd44780_clear_line(uint8_t line){

uint8_t x;

hd44780_set_cursor(line,0);

for(x=0;x<DISP_LEN;x++){

hd44780_data(' ');

}

hd44780_set_cursor(line,0);

}

void hd44780_print(char * string){

char c;

while ((c = *string++)){

hd44780_data(c);

}

}

void hd44780_print_P(PGM_P string){

char c;

while ((c = pgm_read_byte(string++))){

hd44780_data(c);

}

}

void hd44780_load_font_P(uint8_t charnum, PGM_P data){

uint8_t x, address;

address = hd44780_read();

hd44780_command((uint8_t)(charnum<<3)|0x40); //set cgram address

for (x=0;x<8;x++){

hd44780_data(pgm_read_byte(data++));

}

/*restore position where cursor was */

hd44780_command(0x80|address);

}