/* LCD driver routines



  CodeVisionAVR C Compiler

  © 1998-2007 Pavel Haiduc, HP InfoTech S.R.L.

*/



#asm

.equ __lcd_direction=__lcd_port-1

.equ __lcd_pin=__lcd_port-2

.equ __lcd_rs=0

.equ __lcd_rd=1

.equ __lcd_enable=2

.equ __lcd_busy_flag=7

#endasm



#pragma used+

static unsigned char _base_y[4]={0x80,0xc0};

unsigned char _lcd_x,_lcd_y,_lcd_maxx;

#pragma used-



static void _lcd_delay(void)

{

#asm

ldi   r31,15

__lcd_delay0:

dec   r31

brne  __lcd_delay0

#endasm

}



void _lcd_ready(void)

{

#asm

in r26,__lcd_direction

andi  r26,0xf ;set as input

out   __lcd_direction,r26

sbi   __lcd_port,__lcd_rd ;RD=1

cbi   __lcd_port,__lcd_rs ;RS=0

__lcd_busy:

#endasm

_lcd_delay();

#asm

sbi   __lcd_port,__lcd_enable ;EN=1

#endasm

_lcd_delay();

#asm

in r26,__lcd_pin

cbi   __lcd_port,__lcd_enable ;EN=0

#endasm

_lcd_delay();

#asm

sbi   __lcd_port,__lcd_enable ;EN=1

#endasm

_lcd_delay();

#asm

cbi   __lcd_port,__lcd_enable ;EN=0

sbrc  r26,__lcd_busy_flag

rjmp  __lcd_busy

#endasm

}



static void _lcd_write_nibble(void)

{

#asm

andi  r26,0xf0

or r26,r27

out   __lcd_port,r26   ;write

sbi   __lcd_port,__lcd_enable ;EN=1

#endasm

_lcd_delay();

#asm

cbi   __lcd_port,__lcd_enable ;EN=0

#endasm

_lcd_delay();

}



void _lcd_write_data(unsigned char data)

{

#asm

cbi  __lcd_port,__lcd_rd    ;RD=0

in r26,__lcd_direction

ori   r26,0xf0 | (1<<__lcd_rs) | (1<<__lcd_rd) | (1<<__lcd_enable) ;set as output

out   __lcd_direction,r26

in r27,__lcd_port

andi  r27,0xf

ld r26,y

#endasm

_lcd_write_nibble();    //RD=0, write MSN

#asm

ld r26,y

swap  r26

#endasm

_lcd_write_nibble();    //write LSN

#asm

sbi   __lcd_port,__lcd_rd ;RD=1

#endasm

}



/* write a byte to the LCD character generator or display RAM */

void lcd_write_byte(unsigned char addr, unsigned char data)

{

_lcd_ready();

_lcd_write_data(addr);

_lcd_ready();

#asm

sbi   __lcd_port,__lcd_rs ;RS=1

#endasm

_lcd_write_data(data);

}



static void _lcd_read_nibble(void)

{

#asm

sbi   __lcd_port,__lcd_enable ;EN=1

#endasm

_lcd_delay();

#asm

in r30,__lcd_pin    ;read

cbi   __lcd_port,__lcd_enable ;EN=0

#endasm

_lcd_delay();

#asm

andi  r30,0xf0

#endasm

}



static unsigned char lcd_read_byte0(void)

{

_lcd_delay();

_lcd_read_nibble();    // read MSN

#asm

mov   r26,r30

#endasm

_lcd_read_nibble();    // read LSN

#asm

cbi   __lcd_port,__lcd_rd ;RD=0

swap  r30

or r30,r26

#endasm

}



/* read a byte from the LCD character generator or display RAM */

unsigned char lcd_read_byte(unsigned char addr)

{

_lcd_ready();

_lcd_write_data(addr);

_lcd_ready();

#asm

in r26,__lcd_direction

andi  r26,0xf ;set as input

out   __lcd_direction,r26

sbi   __lcd_port,__lcd_rs ;RS=1

#endasm

return lcd_read_byte0();

}



/* set the LCD display position x=0..39 y=0..3 */

void lcd_gotoxy(unsigned char x, unsigned char y)

{

_lcd_ready(); // RS=0

_lcd_write_data(_base_y[y]+x);

_lcd_x=x;

_lcd_y=y;

}



// clear the LCD

void lcd_clear(void)

{

_lcd_ready(); // RS=0

_lcd_write_data(2);   // cursor home

_lcd_ready();

_lcd_write_data(0xc); // cursor off

_lcd_ready();

_lcd_write_data(1);   // clear

_lcd_x=_lcd_y=0;

}



void lcd_putchar(char c)

{

#asm

push r30

push r31

ld   r26,y

set

cpi  r26,10

breq __lcd_putchar1

clt

#endasm

++_lcd_x;

if (_lcd_x>_lcd_maxx)

   {

   #asm("__lcd_putchar1:")

   ++_lcd_y;

   lcd_gotoxy(0,_lcd_y);

   #asm("brts __lcd_putchar0")

   };

#asm

rcall __lcd_ready

sbi  __lcd_port,__lcd_rs ;RS=1

ld   r26,y

st   -y,r26

rcall __lcd_write_data

__lcd_putchar0:

pop  r31

pop  r30

#endasm

}



// write the string str located in SRAM to the LCD

void lcd_puts(char *str)

{

char k;

while (k=*str++) lcd_putchar(k);

}



// write the string str located in FLASH to the LCD

void lcd_putsf(char flash *str)

{

char k;

while (k=*str++) lcd_putchar(k);

}



static void _long_delay(void)

{

#asm

clr   r26

clr   r27

__long_delay0:

sbiw  r26,1 ;2 cycles

brne  __long_delay0 ;2 cycles

#endasm

}



static void _lcd_init_write(unsigned char data)

{

#asm

cbi  __lcd_port,__lcd_rd    ;RD=0

in r26,__lcd_direction

ori   r26,0xf7 ;set as output

out   __lcd_direction,r26

in r27,__lcd_port

andi  r27,0xf

ld r26,y

#endasm

_lcd_write_nibble();    //RD=0, write MSN

#asm

sbi   __lcd_port,__lcd_rd ;RD=1

#endasm

}



// initialize the LCD controller

unsigned char lcd_init(unsigned char lcd_columns)

{

#asm

cbi   __lcd_port,__lcd_enable ;EN=0

cbi   __lcd_port,__lcd_rs ;RS=0

#endasm

_lcd_maxx=lcd_columns;

_base_y[2]=lcd_columns+0x80;

_base_y[3]=lcd_columns+0xc0;

_long_delay();

_lcd_init_write(0x30);

_long_delay();

_lcd_init_write(0x30);

_long_delay();

_lcd_init_write(0x30);

_long_delay();

_lcd_init_write(0x20);

_long_delay();

_lcd_write_data(0x28);

_long_delay();

_lcd_write_data(4);

_long_delay();

_lcd_write_data(0x85);

_long_delay();

#asm

in r26,__lcd_direction

andi  r26,0xf ;set as input

out   __lcd_direction,r26

sbi   __lcd_port,__lcd_rd ;RD=1

#endasm

if (lcd_read_byte0()!=5) return 0;

_lcd_ready();

_lcd_write_data(6);

lcd_clear();

return 1;

}