qmk-firmware/drivers/avr/hd44780.c

/****************************************************************************
 Title:     HD44780U LCD library
 Author:    Peter Fleury <pfleury@gmx.ch>  http://tinyurl.com/peterfleury
 License:   GNU General Public License Version 3
 File:	    $Id: lcd.c,v 1.15.2.2 2015/01/17 12:16:05 peter Exp $
 Software:  AVR-GCC 3.3
 Target:    any AVR device, memory mapped mode only for AT90S4414/8515/Mega

 DESCRIPTION
       Basic routines for interfacing a HD44780U-based text lcd display

       Originally based on Volker Oth's lcd library,
       changed lcd_init(), added additional constants for lcd_command(),
       added 4-bit I/O mode, improved and optimized code.

       Library can be operated in memory mapped mode (LCD_IO_MODE=0) or in
       4-bit IO port mode (LCD_IO_MODE=1). 8-bit IO port mode not supported.

       Memory mapped mode compatible with Kanda STK200, but supports also
       generation of R/W signal through A8 address line.

 USAGE
       See the C include lcd.h file for a description of each function

*****************************************************************************/
#include <inttypes.h>
#include <avr/io.h>
#include <avr/pgmspace.h>
#include <util/delay.h>
#include "hd44780.h"

/*
** constants/macros
*/
#define DDR(x) (*(&x - 1)) /* address of data direction register of port x */
#if defined(__AVR_ATmega64__) || defined(__AVR_ATmega128__)
/* on ATmega64/128 PINF is on port 0x00 and not 0x60 */
#    define PIN(x) (&PORTF == &(x) ? _SFR_IO8(0x00) : (*(&x - 2)))
#else
#    define PIN(x) (*(&x - 2)) /* address of input register of port x          */
#endif

#if LCD_IO_MODE
#    define lcd_e_delay() _delay_us(LCD_DELAY_ENABLE_PULSE)
#    define lcd_e_high() LCD_E_PORT |= _BV(LCD_E_PIN);
#    define lcd_e_low() LCD_E_PORT &= ~_BV(LCD_E_PIN);
#    define lcd_e_toggle() toggle_e()
#    define lcd_rw_high() LCD_RW_PORT |= _BV(LCD_RW_PIN)
#    define lcd_rw_low() LCD_RW_PORT &= ~_BV(LCD_RW_PIN)
#    define lcd_rs_high() LCD_RS_PORT |= _BV(LCD_RS_PIN)
#    define lcd_rs_low() LCD_RS_PORT &= ~_BV(LCD_RS_PIN)
#endif

#if LCD_IO_MODE
#    if LCD_LINES == 1
#        define LCD_FUNCTION_DEFAULT LCD_FUNCTION_4BIT_1LINE
#    else
#        define LCD_FUNCTION_DEFAULT LCD_FUNCTION_4BIT_2LINES
#    endif
#else
#    if LCD_LINES == 1
#        define LCD_FUNCTION_DEFAULT LCD_FUNCTION_8BIT_1LINE
#    else
#        define LCD_FUNCTION_DEFAULT LCD_FUNCTION_8BIT_2LINES
#    endif
#endif

#if LCD_CONTROLLER_KS0073
#    if LCD_LINES == 4

#        define KS0073_EXTENDED_FUNCTION_REGISTER_ON 0x2C  /* |0|010|1100 4-bit mode, extension-bit RE = 1 */
#        define KS0073_EXTENDED_FUNCTION_REGISTER_OFF 0x28 /* |0|010|1000 4-bit mode, extension-bit RE = 0 */
#        define KS0073_4LINES_MODE 0x09                    /* |0|000|1001 4 lines mode */

#    endif
#endif

/*
** function prototypes
*/
#if LCD_IO_MODE
static void toggle_e(void);
#endif

/*
** local functions
*/

/*************************************************************************
delay for a minimum of <us> microseconds
the number of loops is calculated at compile-time from MCU clock frequency
*************************************************************************/
#define delay(us) _delay_us(us)

#if LCD_IO_MODE
/* toggle Enable Pin to initiate write */
static void toggle_e(void) {
    lcd_e_high();
    lcd_e_delay();
    lcd_e_low();
}
#endif

/*************************************************************************
Low-level function to write byte to LCD controller
Input:    data   byte to write to LCD
          rs     1: write data
                 0: write instruction
Returns:  none
*************************************************************************/
#if LCD_IO_MODE
static void lcd_write(uint8_t data, uint8_t rs) {
    unsigned char dataBits;

    if (rs) { /* write data        (RS=1, RW=0) */
        lcd_rs_high();
    } else { /* write instruction (RS=0, RW=0) */
        lcd_rs_low();
    }
    lcd_rw_low(); /* RW=0  write mode      */

    if ((&LCD_DATA0_PORT == &LCD_DATA1_PORT) && (&LCD_DATA1_PORT == &LCD_DATA2_PORT) && (&LCD_DATA2_PORT == &LCD_DATA3_PORT) && (LCD_DATA0_PIN == 0) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3)) {
        /* configure data pins as output */
        DDR(LCD_DATA0_PORT) |= 0x0F;

        /* output high nibble first */
        dataBits       = LCD_DATA0_PORT & 0xF0;
        LCD_DATA0_PORT = dataBits | ((data >> 4) & 0x0F);
        lcd_e_toggle();

        /* output low nibble */
        LCD_DATA0_PORT = dataBits | (data & 0x0F);
        lcd_e_toggle();

        /* all data pins high (inactive) */
        LCD_DATA0_PORT = dataBits | 0x0F;
    } else {
        /* configure data pins as output */
        DDR(LCD_DATA0_PORT) |= _BV(LCD_DATA0_PIN);
        DDR(LCD_DATA1_PORT) |= _BV(LCD_DATA1_PIN);
        DDR(LCD_DATA2_PORT) |= _BV(LCD_DATA2_PIN);
        DDR(LCD_DATA3_PORT) |= _BV(LCD_DATA3_PIN);

        /* output high nibble first */
        LCD_DATA3_PORT &= ~_BV(LCD_DATA3_PIN);
        LCD_DATA2_PORT &= ~_BV(LCD_DATA2_PIN);
        LCD_DATA1_PORT &= ~_BV(LCD_DATA1_PIN);
        LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN);
        if (data & 0x80) LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
        if (data & 0x40) LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
        if (data & 0x20) LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
        if (data & 0x10) LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
        lcd_e_toggle();

        /* output low nibble */
        LCD_DATA3_PORT &= ~_BV(LCD_DATA3_PIN);
        LCD_DATA2_PORT &= ~_BV(LCD_DATA2_PIN);
        LCD_DATA1_PORT &= ~_BV(LCD_DATA1_PIN);
        LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN);
        if (data & 0x08) LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
        if (data & 0x04) LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
        if (data & 0x02) LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
        if (data & 0x01) LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
        lcd_e_toggle();

        /* all data pins high (inactive) */
        LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
        LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
        LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
        LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
    }
}
#else
#    define lcd_write(d, rs)                        \
        if (rs)                                     \
            *(volatile uint8_t *)(LCD_IO_DATA) = d; \
        else                                        \
            *(volatile uint8_t *)(LCD_IO_FUNCTION) = d;
/* rs==0 -> write instruction to LCD_IO_FUNCTION */
/* rs==1 -> write data to LCD_IO_DATA */
#endif

/*************************************************************************
Low-level function to read byte from LCD controller
Input:    rs     1: read data
                 0: read busy flag / address counter
Returns:  byte read from LCD controller
*************************************************************************/
#if LCD_IO_MODE
static uint8_t lcd_read(uint8_t rs) {
    uint8_t data;

    if (rs)
        lcd_rs_high(); /* RS=1: read data      */
    else
        lcd_rs_low(); /* RS=0: read busy flag */
    lcd_rw_high();    /* RW=1  read mode      */

    if ((&LCD_DATA0_PORT == &LCD_DATA1_PORT) && (&LCD_DATA1_PORT == &LCD_DATA2_PORT) && (&LCD_DATA2_PORT == &LCD_DATA3_PORT) && (LCD_DATA0_PIN == 0) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3)) {
        DDR(LCD_DATA0_PORT) &= 0xF0; /* configure data pins as input */

        lcd_e_high();
        lcd_e_delay();
        data = PIN(LCD_DATA0_PORT) << 4; /* read high nibble first */
        lcd_e_low();

        lcd_e_delay(); /* Enable 500ns low       */

        lcd_e_high();
        lcd_e_delay();
        data |= PIN(LCD_DATA0_PORT) & 0x0F; /* read low nibble        */
        lcd_e_low();
    } else {
        /* configure data pins as input */
        DDR(LCD_DATA0_PORT) &= ~_BV(LCD_DATA0_PIN);
        DDR(LCD_DATA1_PORT) &= ~_BV(LCD_DATA1_PIN);
        DDR(LCD_DATA2_PORT) &= ~_BV(LCD_DATA2_PIN);
        DDR(LCD_DATA3_PORT) &= ~_BV(LCD_DATA3_PIN);

        /* read high nibble first */
        lcd_e_high();
        lcd_e_delay();
        data = 0;
        if (PIN(LCD_DATA0_PORT) & _BV(LCD_DATA0_PIN)) data |= 0x10;
        if (PIN(LCD_DATA1_PORT) & _BV(LCD_DATA1_PIN)) data |= 0x20;
        if (PIN(LCD_DATA2_PORT) & _BV(LCD_DATA2_PIN)) data |= 0x40;
        if (PIN(LCD_DATA3_PORT) & _BV(LCD_DATA3_PIN)) data |= 0x80;
        lcd_e_low();

        lcd_e_delay(); /* Enable 500ns low       */

        /* read low nibble */
        lcd_e_high();
        lcd_e_delay();
        if (PIN(LCD_DATA0_PORT) & _BV(LCD_DATA0_PIN)) data |= 0x01;
        if (PIN(LCD_DATA1_PORT) & _BV(LCD_DATA1_PIN)) data |= 0x02;
        if (PIN(LCD_DATA2_PORT) & _BV(LCD_DATA2_PIN)) data |= 0x04;
        if (PIN(LCD_DATA3_PORT) & _BV(LCD_DATA3_PIN)) data |= 0x08;
        lcd_e_low();
    }
    return data;
}
#else
#    define lcd_read(rs) (rs) ? *(volatile uint8_t *)(LCD_IO_DATA + LCD_IO_READ) : *(volatile uint8_t *)(LCD_IO_FUNCTION + LCD_IO_READ)
/* rs==0 -> read instruction from LCD_IO_FUNCTION */
/* rs==1 -> read data from LCD_IO_DATA */
#endif

/*************************************************************************
loops while lcd is busy, returns address counter
*************************************************************************/
static uint8_t lcd_waitbusy(void)

{
    register uint8_t c;

    /* wait until busy flag is cleared */
    while ((c = lcd_read(0)) & (1 << LCD_BUSY)) {
    }

    /* the address counter is updated 4us after the busy flag is cleared */
    delay(LCD_DELAY_BUSY_FLAG);

    /* now read the address counter */
    return (lcd_read(0));  // return address counter

} /* lcd_waitbusy */

/*************************************************************************
Move cursor to the start of next line or to the first line if the cursor
is already on the last line.
*************************************************************************/
static inline void lcd_newline(uint8_t pos) {
    register uint8_t addressCounter;

#if LCD_LINES == 1
    addressCounter = 0;
#endif
#if LCD_LINES == 2
    if (pos < (LCD_START_LINE2))
        addressCounter = LCD_START_LINE2;
    else
        addressCounter = LCD_START_LINE1;
#endif
#if LCD_LINES == 4
#    if KS0073_4LINES_MODE
    if (pos < LCD_START_LINE2)
        addressCounter = LCD_START_LINE2;
    else if ((pos >= LCD_START_LINE2) && (pos < LCD_START_LINE3))
        addressCounter = LCD_START_LINE3;
    else if ((pos >= LCD_START_LINE3) && (pos < LCD_START_LINE4))
        addressCounter = LCD_START_LINE4;
    else
        addressCounter = LCD_START_LINE1;
#    else
    if (pos < LCD_START_LINE3)
        addressCounter = LCD_START_LINE2;
    else if ((pos >= LCD_START_LINE2) && (pos < LCD_START_LINE4))
        addressCounter = LCD_START_LINE3;
    else if ((pos >= LCD_START_LINE3) && (pos < LCD_START_LINE2))
        addressCounter = LCD_START_LINE4;
    else
        addressCounter = LCD_START_LINE1;
#    endif
#endif
    lcd_command((1 << LCD_DDRAM) + addressCounter);

} /* lcd_newline */

/*
** PUBLIC FUNCTIONS
*/

/*************************************************************************
Send LCD controller instruction command
Input:   instruction to send to LCD controller, see HD44780 data sheet
Returns: none
*************************************************************************/
void lcd_command(uint8_t cmd) {
    lcd_waitbusy();
    lcd_write(cmd, 0);
}

/*************************************************************************
Send data byte to LCD controller
Input:   data to send to LCD controller, see HD44780 data sheet
Returns: none
*************************************************************************/
void lcd_data(uint8_t data) {
    lcd_waitbusy();
    lcd_write(data, 1);
}

/*************************************************************************
Set cursor to specified position
Input:    x  horizontal position  (0: left most position)
          y  vertical position    (0: first line)
Returns:  none
*************************************************************************/
void lcd_gotoxy(uint8_t x, uint8_t y) {
#if LCD_LINES == 1
    lcd_command((1 << LCD_DDRAM) + LCD_START_LINE1 + x);
#endif
#if LCD_LINES == 2
    if (y == 0)
        lcd_command((1 << LCD_DDRAM) + LCD_START_LINE1 + x);
    else
        lcd_command((1 << LCD_DDRAM) + LCD_START_LINE2 + x);
#endif
#if LCD_LINES == 4
    if (y == 0)
        lcd_command((1 << LCD_DDRAM) + LCD_START_LINE1 + x);
    else if (y == 1)
        lcd_command((1 << LCD_DDRAM) + LCD_START_LINE2 + x);
    else if (y == 2)
        lcd_command((1 << LCD_DDRAM) + LCD_START_LINE3 + x);
    else /* y==3 */
        lcd_command((1 << LCD_DDRAM) + LCD_START_LINE4 + x);
#endif

} /* lcd_gotoxy */

/*************************************************************************
*************************************************************************/
int lcd_getxy(void) { return lcd_waitbusy(); }

/*************************************************************************
Clear display and set cursor to home position
*************************************************************************/
void lcd_clrscr(void) { lcd_command(1 << LCD_CLR); }

/*************************************************************************
Set cursor to home position
*************************************************************************/
void lcd_home(void) { lcd_command(1 << LCD_HOME); }

/*************************************************************************
Display character at current cursor position
Input:    character to be displayed
Returns:  none
*************************************************************************/
void lcd_putc(char c) {
    uint8_t pos;

    pos = lcd_waitbusy();  // read busy-flag and address counter
    if (c == '\n') {
        lcd_newline(pos);
    } else {
#if LCD_WRAP_LINES == 1
#    if LCD_LINES == 1
        if (pos == LCD_START_LINE1 + LCD_DISP_LENGTH) {
            lcd_write((1 << LCD_DDRAM) + LCD_START_LINE1, 0);
        }
#    elif LCD_LINES == 2
        if (pos == LCD_START_LINE1 + LCD_DISP_LENGTH) {
            lcd_write((1 << LCD_DDRAM) + LCD_START_LINE2, 0);
        } else if (pos == LCD_START_LINE2 + LCD_DISP_LENGTH) {
            lcd_write((1 << LCD_DDRAM) + LCD_START_LINE1, 0);
        }
#    elif LCD_LINES == 4
        if (pos == LCD_START_LINE1 + LCD_DISP_LENGTH) {
            lcd_write((1 << LCD_DDRAM) + LCD_START_LINE2, 0);
        } else if (pos == LCD_START_LINE2 + LCD_DISP_LENGTH) {
            lcd_write((1 << LCD_DDRAM) + LCD_START_LINE3, 0);
        } else if (pos == LCD_START_LINE3 + LCD_DISP_LENGTH) {
            lcd_write((1 << LCD_DDRAM) + LCD_START_LINE4, 0);
        } else if (pos == LCD_START_LINE4 + LCD_DISP_LENGTH) {
            lcd_write((1 << LCD_DDRAM) + LCD_START_LINE1, 0);
        }
#    endif
        lcd_waitbusy();
#endif
        lcd_write(c, 1);
    }

} /* lcd_putc */

/*************************************************************************
Display string without auto linefeed
Input:    string to be displayed
Returns:  none
*************************************************************************/
void lcd_puts(const char *s)
/* print string on lcd (no auto linefeed) */
{
    register char c;

    while ((c = *s++)) {
        lcd_putc(c);
    }

} /* lcd_puts */

/*************************************************************************
Display string from program memory without auto linefeed
Input:     string from program memory be be displayed
Returns:   none
*************************************************************************/
void lcd_puts_p(const char *progmem_s)
/* print string from program memory on lcd (no auto linefeed) */
{
    register char c;

    while ((c = pgm_read_byte(progmem_s++))) {
        lcd_putc(c);
    }

} /* lcd_puts_p */

/*************************************************************************
Initialize display and select type of cursor
Input:    dispAttr LCD_DISP_OFF            display off
                   LCD_DISP_ON             display on, cursor off
                   LCD_DISP_ON_CURSOR      display on, cursor on
                   LCD_DISP_CURSOR_BLINK   display on, cursor on flashing
Returns:  none
*************************************************************************/
void lcd_init(uint8_t dispAttr) {
#if LCD_IO_MODE
    /*
     *  Initialize LCD to 4 bit I/O mode
     */

    if ((&LCD_DATA0_PORT == &LCD_DATA1_PORT) && (&LCD_DATA1_PORT == &LCD_DATA2_PORT) && (&LCD_DATA2_PORT == &LCD_DATA3_PORT) && (&LCD_RS_PORT == &LCD_DATA0_PORT) && (&LCD_RW_PORT == &LCD_DATA0_PORT) && (&LCD_E_PORT == &LCD_DATA0_PORT) && (LCD_DATA0_PIN == 0) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3) && (LCD_RS_PIN == 4) && (LCD_RW_PIN == 5) && (LCD_E_PIN == 6)) {
        /* configure all port bits as output (all LCD lines on same port) */
        DDR(LCD_DATA0_PORT) |= 0x7F;
    } else if ((&LCD_DATA0_PORT == &LCD_DATA1_PORT) && (&LCD_DATA1_PORT == &LCD_DATA2_PORT) && (&LCD_DATA2_PORT == &LCD_DATA3_PORT) && (LCD_DATA0_PIN == 0) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3)) {
        /* configure all port bits as output (all LCD data lines on same port, but control lines on different ports) */
        DDR(LCD_DATA0_PORT) |= 0x0F;
        DDR(LCD_RS_PORT) |= _BV(LCD_RS_PIN);
        DDR(LCD_RW_PORT) |= _BV(LCD_RW_PIN);
        DDR(LCD_E_PORT) |= _BV(LCD_E_PIN);
    } else {
        /* configure all port bits as output (LCD data and control lines on different ports */
        DDR(LCD_RS_PORT) |= _BV(LCD_RS_PIN);
        DDR(LCD_RW_PORT) |= _BV(LCD_RW_PIN);
        DDR(LCD_E_PORT) |= _BV(LCD_E_PIN);
        DDR(LCD_DATA0_PORT) |= _BV(LCD_DATA0_PIN);
        DDR(LCD_DATA1_PORT) |= _BV(LCD_DATA1_PIN);
        DDR(LCD_DATA2_PORT) |= _BV(LCD_DATA2_PIN);
        DDR(LCD_DATA3_PORT) |= _BV(LCD_DATA3_PIN);
    }
    delay(LCD_DELAY_BOOTUP); /* wait 16ms or more after power-on       */

    /* initial write to lcd is 8bit */
    LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);  // LCD_FUNCTION>>4;
    LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);  // LCD_FUNCTION_8BIT>>4;
    lcd_e_toggle();
    delay(LCD_DELAY_INIT); /* delay, busy flag can't be checked here */

    /* repeat last command */
    lcd_e_toggle();
    delay(LCD_DELAY_INIT_REP); /* delay, busy flag can't be checked here */

    /* repeat last command a third time */
    lcd_e_toggle();
    delay(LCD_DELAY_INIT_REP); /* delay, busy flag can't be checked here */

    /* now configure for 4bit mode */
    LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN);  // LCD_FUNCTION_4BIT_1LINE>>4
    lcd_e_toggle();
    delay(LCD_DELAY_INIT_4BIT); /* some displays need this additional delay */

    /* from now the LCD only accepts 4 bit I/O, we can use lcd_command() */
#else
    /*
     * Initialize LCD to 8 bit memory mapped mode
     */

    /* enable external SRAM (memory mapped lcd) and one wait state */
    MCUCR = _BV(SRE) | _BV(SRW);

    /* reset LCD */
    delay(LCD_DELAY_BOOTUP);               /* wait 16ms after power-on     */
    lcd_write(LCD_FUNCTION_8BIT_1LINE, 0); /* function set: 8bit interface */
    delay(LCD_DELAY_INIT);                 /* wait 5ms                     */
    lcd_write(LCD_FUNCTION_8BIT_1LINE, 0); /* function set: 8bit interface */
    delay(LCD_DELAY_INIT_REP);             /* wait 64us                    */
    lcd_write(LCD_FUNCTION_8BIT_1LINE, 0); /* function set: 8bit interface */
    delay(LCD_DELAY_INIT_REP);             /* wait 64us                    */
#endif

#if KS0073_4LINES_MODE
    /* Display with KS0073 controller requires special commands for enabling 4 line mode */
    lcd_command(KS0073_EXTENDED_FUNCTION_REGISTER_ON);
    lcd_command(KS0073_4LINES_MODE);
    lcd_command(KS0073_EXTENDED_FUNCTION_REGISTER_OFF);
#else
    lcd_command(LCD_FUNCTION_DEFAULT);     /* function set: display lines  */
#endif
    lcd_command(LCD_DISP_OFF);     /* display off                  */
    lcd_clrscr();                  /* display clear                */
    lcd_command(LCD_MODE_DEFAULT); /* set entry mode               */
    lcd_command(dispAttr);         /* display/cursor control       */

} /* lcd_init */