Integrating Peter Fleury's HD44780 LCD library (#3209)

* integrated Peter Fleury's LCD library for HD44780 LCDs

* fixed typo

* cleanup finished

* add documentation

* added HD44780 documentation

* removed keyboard from .gitmodules

* resolved merge conflict

* removed edit of kira75s rules.mk made by merge

* moved hd44780 to drivers/avr

* Added licence info to hd44780 files

* Added link to hd44780 docs.

common_features.mk

@@ -197,6 +197,12 @@ ifeq ($(strip $(USB_HID_ENABLE)), yes)
     include $(TMK_DIR)/protocol/usb_hid.mk
 endif
 
+
+ifeq ($(strip $(HD44780_ENABLE)), yes)
+    SRC += drivers/avr/hd44780.c
+	OPT_DEFS += -DHD44780_ENABLE
+endif
+
 QUANTUM_SRC:= \
     $(QUANTUM_DIR)/quantum.c \
     $(QUANTUM_DIR)/keymap_common.c \

docs/feature_hd44780.md

@@ -0,0 +1,56 @@
+# HD44780 LCD Displays
+
+This is an integration of Peter Fleury's LCD library. This page will explain the basics. [For in depth documentation visit his page.](http://homepage.hispeed.ch/peterfleury/doxygen/avr-gcc-libraries/group__pfleury__lcd.html)
+
+You can enable support for HD44780 Displays by setting the `HD44780_ENABLE` flag in your keyboards `rules.mk` to yes. This will use about 400 KB of extra space.
+
+## Configuration
+
+You will need to configure the pins used by your display and its number of lines and collumn in your keyboards `config.h`.
+
+Uncomment the section labled HD44780 and change the parameters as needed.
+````
+/*
+ * HD44780 LCD Display Configuration
+ */
+
+#define LCD_LINES           2     //< number of visible lines of the display
+#define LCD_DISP_LENGTH    16     //< visibles characters per line of the display
+#define LCD_IO_MODE      1            //< 0: memory mapped mode, 1: IO port mode
+#if LCD_IO_MODE
+#define LCD_PORT         PORTB        //< port for the LCD lines
+#define LCD_DATA0_PORT   LCD_PORT     //< port for 4bit data bit 0
+#define LCD_DATA1_PORT   LCD_PORT     //< port for 4bit data bit 1
+#define LCD_DATA2_PORT   LCD_PORT     //< port for 4bit data bit 2
+#define LCD_DATA3_PORT   LCD_PORT     //< port for 4bit data bit 3
+#define LCD_DATA0_PIN    4            //< pin for 4bit data bit 0
+#define LCD_DATA1_PIN    5            //< pin for 4bit data bit 1
+#define LCD_DATA2_PIN    6            //< pin for 4bit data bit 2 
+#define LCD_DATA3_PIN    7            //< pin for 4bit data bit 3
+#define LCD_RS_PORT      LCD_PORT     //< port for RS line        
+#define LCD_RS_PIN       3            //< pin  for RS line        
+#define LCD_RW_PORT      LCD_PORT     //< port for RW line        
+#define LCD_RW_PIN       2            //< pin  for RW line        
+#define LCD_E_PORT       LCD_PORT     //< port for Enable line     
+#define LCD_E_PIN        1            //< pin  for Enable line    
+#endif
+````
+
+Should you need to configure other properties you can copy them from `quantum/hd44780.h` and set them in your `config.h`
+
+## Usage 
+
+To initialize your display call lcd_init() with one of these parameters:
+````
+LCD_DISP_OFF             : display off
+LCD_DISP_ON              : display on, cursor off
+LCD_DISP_ON_CURSOR       : display on, cursor on
+LCD_DISP_ON_CURSOR_BLINK : display on, cursor on flashing 
+````
+This is best done in your keyboards `matrix_init_kb` or your keymaps `matrix_init_user`.  
+It is advised to clear the display before use.  
+To do so call `lcd_clrsrc()`.
+
+To now print something to your Display you first call `lcd_gotoxy(column, line)`. To go to the start of the first line you would call `lcd_gotoxy(0, 0)` and then print a string with `lcd_puts("example string")`.
+
+There are more posible methods to control the display. [For in depth documentation please visit the linked page.](http://homepage.hispeed.ch/peterfleury/doxygen/avr-gcc-libraries/group__pfleury__lcd.html)

docs/features.md

@@ -9,6 +9,7 @@ QMK has a staggering number of features for building your keyboard. It can take
 * [Backlight](feature_backlight.md) - LED lighting support for your keyboard.
 * [Bootmagic](feature_bootmagic.md) - Adjust the behavior of your keyboard using hotkeys.
 * [Dynamic Macros](feature_dynamic_macros.md) - Record and playback macros from the keyboard itself.
+* [HD44780 LCD Display](feature_hd44780.md) - Support for LCD character displays using the HD44780 standard.
 * [Key Lock](feature_key_lock.md) - Lock a key in the "down" state.
 * [Layouts](feature_layouts.md) - Use one keymap with any keyboard that supports your layout.
 * [Leader Key](feature_leader_key.md) - Tap the leader key followed by a sequence to trigger custom behavior.

drivers/avr/hd44780.c

@@ -0,0 +1,592 @@
+/****************************************************************************
+ 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 */
+

drivers/avr/hd44780.h

@@ -0,0 +1,371 @@
+#ifndef LCD_H
+#define LCD_H
+/*************************************************************************
+ Title	:   C include file for the HD44780U LCD library (lcd.c)
+ Author:    Peter Fleury <pfleury@gmx.ch>  http://tinyurl.com/peterfleury
+ License:   GNU General Public License Version 3
+ File:	    $Id: lcd.h,v 1.14.2.4 2015/01/20 17:16:07 peter Exp $
+ Software:  AVR-GCC 4.x
+ Hardware:  any AVR device, memory mapped mode only for AVR with 
+            memory mapped interface (AT90S8515/ATmega8515/ATmega128)
+***************************************************************************/
+
+/**
+ @mainpage
+ Collection of libraries for AVR-GCC
+ @author Peter Fleury pfleury@gmx.ch http://tinyurl.com/peterfleury
+ @copyright (C) 2015 Peter Fleury, GNU General Public License Version 3
+ 
+ @file
+ @defgroup pfleury_lcd LCD library <lcd.h>
+ @code #include <lcd.h> @endcode
+ 
+ @brief Basic routines for interfacing a HD44780U-based character LCD display
+
+ LCD character displays can be found in many devices, like espresso machines, laser printers. 
+ The Hitachi HD44780 controller and its compatible controllers like Samsung KS0066U have become an industry standard for these types of displays. 
+ 
+ This library allows easy interfacing with a HD44780 compatible display and can be
+ operated in memory mapped mode (LCD_IO_MODE defined as 0 in the include file lcd.h.) or in 
+ 4-bit IO port mode (LCD_IO_MODE defined as 1). 8-bit IO port mode is not supported.
+
+ Memory mapped mode is compatible with old Kanda STK200 starter kit, but also supports
+ generation of R/W signal through A8 address line.
+
+ @see The chapter <a href=" http://homepage.hispeed.ch/peterfleury/avr-lcd44780.html" target="_blank">Interfacing a HD44780 Based LCD to an AVR</a>
+      on my home page, which shows example circuits how to connect an LCD to an AVR controller. 
+
+ @author Peter Fleury pfleury@gmx.ch http://tinyurl.com/peterfleury
+ 
+ @version   2.0
+ 
+ @copyright (C) 2015 Peter Fleury, GNU General Public License Version 3
+  
+*/
+
+#include <inttypes.h>
+#include <avr/pgmspace.h>
+
+#if (__GNUC__ * 100 + __GNUC_MINOR__) < 405
+#error "This library requires AVR-GCC 4.5 or later, update to newer AVR-GCC compiler !"
+#endif
+
+
+/**@{*/
+
+/*
+ * LCD and target specific definitions below can be defined in a separate include file with name lcd_definitions.h instead modifying this file 
+ * by adding -D_LCD_DEFINITIONS_FILE to the CDEFS section in the Makefile
+ * All definitions added to the file lcd_definitions.h will override the default definitions from lcd.h
+ */
+#ifdef _LCD_DEFINITIONS_FILE
+#include "lcd_definitions.h"
+#endif
+
+
+/**
+ * @name  Definition for LCD controller type
+ * Use 0 for HD44780 controller, change to 1 for displays with KS0073 controller.
+ */
+#ifndef LCD_CONTROLLER_KS0073 
+#define LCD_CONTROLLER_KS0073 0  /**< Use 0 for HD44780 controller, 1 for KS0073 controller */
+#endif
+
+/** 
+ * @name  Definitions for Display Size 
+ * Change these definitions to adapt setting to your display
+ *
+ * These definitions can be defined in a separate include file \b lcd_definitions.h instead modifying this file by 
+ * adding -D_LCD_DEFINITIONS_FILE to the CDEFS section in the Makefile.
+ * All definitions added to the file lcd_definitions.h will override the default definitions from lcd.h
+ *
+ */
+#ifndef LCD_LINES
+#define LCD_LINES           2     /**< number of visible lines of the display */
+#endif
+#ifndef LCD_DISP_LENGTH
+#define LCD_DISP_LENGTH    16     /**< visibles characters per line of the display */
+#endif
+#ifndef LCD_LINE_LENGTH
+#define LCD_LINE_LENGTH  0x40     /**< internal line length of the display    */
+#endif
+#ifndef LCD_START_LINE1
+#define LCD_START_LINE1  0x00     /**< DDRAM address of first char of line 1 */
+#endif
+#ifndef LCD_START_LINE2
+#define LCD_START_LINE2  0x40     /**< DDRAM address of first char of line 2 */
+#endif
+#ifndef LCD_START_LINE3
+#define LCD_START_LINE3  0x14     /**< DDRAM address of first char of line 3 */
+#endif
+#ifndef LCD_START_LINE4
+#define LCD_START_LINE4  0x54     /**< DDRAM address of first char of line 4 */
+#endif
+#ifndef LCD_WRAP_LINES
+#define LCD_WRAP_LINES      0     /**< 0: no wrap, 1: wrap at end of visibile line */
+#endif
+
+
+/**
+ * @name Definitions for 4-bit IO mode
+ *
+ * The four LCD data lines and the three control lines RS, RW, E can be on the 
+ * same port or on different ports. 
+ * Change LCD_RS_PORT, LCD_RW_PORT, LCD_E_PORT if you want the control lines on
+ * different ports. 
+ *
+ * Normally the four data lines should be mapped to bit 0..3 on one port, but it
+ * is possible to connect these data lines in different order or even on different
+ * ports by adapting the LCD_DATAx_PORT and LCD_DATAx_PIN definitions.
+ *
+ * Adjust these definitions to your target.\n 
+ * These definitions can be defined in a separate include file \b lcd_definitions.h instead modifying this file by 
+ * adding \b -D_LCD_DEFINITIONS_FILE to the \b CDEFS section in the Makefile.
+ * All definitions added to the file lcd_definitions.h will override the default definitions from lcd.h
+ *  
+ */
+#define LCD_IO_MODE      1            /**< 0: memory mapped mode, 1: IO port mode */
+
+#if LCD_IO_MODE
+
+#ifndef LCD_PORT
+#define LCD_PORT         PORTA        /**< port for the LCD lines   */
+#endif
+#ifndef LCD_DATA0_PORT
+#define LCD_DATA0_PORT   LCD_PORT     /**< port for 4bit data bit 0 */
+#endif
+#ifndef LCD_DATA1_PORT
+#define LCD_DATA1_PORT   LCD_PORT     /**< port for 4bit data bit 1 */
+#endif
+#ifndef LCD_DATA2_PORT
+#define LCD_DATA2_PORT   LCD_PORT     /**< port for 4bit data bit 2 */
+#endif
+#ifndef LCD_DATA3_PORT
+#define LCD_DATA3_PORT   LCD_PORT     /**< port for 4bit data bit 3 */
+#endif
+#ifndef LCD_DATA0_PIN
+#define LCD_DATA0_PIN    4            /**< pin for 4bit data bit 0  */
+#endif
+#ifndef LCD_DATA1_PIN
+#define LCD_DATA1_PIN    5            /**< pin for 4bit data bit 1  */
+#endif
+#ifndef LCD_DATA2_PIN
+#define LCD_DATA2_PIN    6            /**< pin for 4bit data bit 2  */
+#endif
+#ifndef LCD_DATA3_PIN
+#define LCD_DATA3_PIN    7            /**< pin for 4bit data bit 3  */
+#endif
+#ifndef LCD_RS_PORT
+#define LCD_RS_PORT      LCD_PORT     /**< port for RS line         */
+#endif
+#ifndef LCD_RS_PIN
+#define LCD_RS_PIN       3            /**< pin  for RS line         */
+#endif
+#ifndef LCD_RW_PORT
+#define LCD_RW_PORT      LCD_PORT     /**< port for RW line         */
+#endif
+#ifndef LCD_RW_PIN
+#define LCD_RW_PIN       2            /**< pin  for RW line         */
+#endif
+#ifndef LCD_E_PORT
+#define LCD_E_PORT       LCD_PORT     /**< port for Enable line     */
+#endif
+#ifndef LCD_E_PIN
+#define LCD_E_PIN        1            /**< pin  for Enable line     */
+#endif
+
+#elif defined(__AVR_AT90S4414__) || defined(__AVR_AT90S8515__) || defined(__AVR_ATmega64__) || \
+      defined(__AVR_ATmega8515__)|| defined(__AVR_ATmega103__) || defined(__AVR_ATmega128__) || \
+      defined(__AVR_ATmega161__) || defined(__AVR_ATmega162__)
+/*
+ * memory mapped mode is only supported when the device has an external data memory interface
+ */
+#define LCD_IO_DATA      0xC000    /* A15=E=1, A14=RS=1                 */
+#define LCD_IO_FUNCTION  0x8000    /* A15=E=1, A14=RS=0                 */
+#define LCD_IO_READ      0x0100    /* A8 =R/W=1 (R/W: 1=Read, 0=Write   */
+
+#else
+#error "external data memory interface not available for this device, use 4-bit IO port mode"
+
+#endif
+
+
+/**
+ * @name Definitions of delays
+ * Used to calculate delay timers.
+ * Adapt the F_CPU define in the Makefile to the clock frequency in Hz of your target
+ *
+ * These delay times can be adjusted, if some displays require different delays.\n 
+ * These definitions can be defined in a separate include file \b lcd_definitions.h instead modifying this file by 
+ * adding \b -D_LCD_DEFINITIONS_FILE to the \b CDEFS section in the Makefile.
+ * All definitions added to the file lcd_definitions.h will override the default definitions from lcd.h
+ */
+#ifndef LCD_DELAY_BOOTUP
+#define LCD_DELAY_BOOTUP   16000      /**< delay in micro seconds after power-on  */
+#endif
+#ifndef LCD_DELAY_INIT
+#define LCD_DELAY_INIT      5000      /**< delay in micro seconds after initialization command sent  */
+#endif
+#ifndef LCD_DELAY_INIT_REP
+#define LCD_DELAY_INIT_REP    64      /**< delay in micro seconds after initialization command repeated */
+#endif
+#ifndef LCD_DELAY_INIT_4BIT
+#define LCD_DELAY_INIT_4BIT   64      /**< delay in micro seconds after setting 4-bit mode */ 
+#endif
+#ifndef LCD_DELAY_BUSY_FLAG
+#define LCD_DELAY_BUSY_FLAG    4      /**< time in micro seconds the address counter is updated after busy flag is cleared */
+#endif
+#ifndef LCD_DELAY_ENABLE_PULSE
+#define LCD_DELAY_ENABLE_PULSE 1      /**< enable signal pulse width in micro seconds */
+#endif
+
+
+/**
+ * @name Definitions for LCD command instructions
+ * The constants define the various LCD controller instructions which can be passed to the 
+ * function lcd_command(), see HD44780 data sheet for a complete description.
+ */
+
+/* instruction register bit positions, see HD44780U data sheet */
+#define LCD_CLR               0      /* DB0: clear display                  */
+#define LCD_HOME              1      /* DB1: return to home position        */
+#define LCD_ENTRY_MODE        2      /* DB2: set entry mode                 */
+#define LCD_ENTRY_INC         1      /*   DB1: 1=increment, 0=decrement     */
+#define LCD_ENTRY_SHIFT       0      /*   DB2: 1=display shift on           */
+#define LCD_ON                3      /* DB3: turn lcd/cursor on             */
+#define LCD_ON_DISPLAY        2      /*   DB2: turn display on              */
+#define LCD_ON_CURSOR         1      /*   DB1: turn cursor on               */
+#define LCD_ON_BLINK          0      /*     DB0: blinking cursor ?          */
+#define LCD_MOVE              4      /* DB4: move cursor/display            */
+#define LCD_MOVE_DISP         3      /*   DB3: move display (0-> cursor) ?  */
+#define LCD_MOVE_RIGHT        2      /*   DB2: move right (0-> left) ?      */
+#define LCD_FUNCTION          5      /* DB5: function set                   */
+#define LCD_FUNCTION_8BIT     4      /*   DB4: set 8BIT mode (0->4BIT mode) */
+#define LCD_FUNCTION_2LINES   3      /*   DB3: two lines (0->one line)      */
+#define LCD_FUNCTION_10DOTS   2      /*   DB2: 5x10 font (0->5x7 font)      */
+#define LCD_CGRAM             6      /* DB6: set CG RAM address             */
+#define LCD_DDRAM             7      /* DB7: set DD RAM address             */
+#define LCD_BUSY              7      /* DB7: LCD is busy                    */
+
+/* set entry mode: display shift on/off, dec/inc cursor move direction */
+#define LCD_ENTRY_DEC            0x04   /* display shift off, dec cursor move dir */
+#define LCD_ENTRY_DEC_SHIFT      0x05   /* display shift on,  dec cursor move dir */
+#define LCD_ENTRY_INC_           0x06   /* display shift off, inc cursor move dir */
+#define LCD_ENTRY_INC_SHIFT      0x07   /* display shift on,  inc cursor move dir */
+
+/* display on/off, cursor on/off, blinking char at cursor position */
+#define LCD_DISP_OFF             0x08   /* display off                            */
+#define LCD_DISP_ON              0x0C   /* display on, cursor off                 */
+#define LCD_DISP_ON_BLINK        0x0D   /* display on, cursor off, blink char     */
+#define LCD_DISP_ON_CURSOR       0x0E   /* display on, cursor on                  */
+#define LCD_DISP_ON_CURSOR_BLINK 0x0F   /* display on, cursor on, blink char      */
+
+/* move cursor/shift display */
+#define LCD_MOVE_CURSOR_LEFT     0x10   /* move cursor left  (decrement)          */
+#define LCD_MOVE_CURSOR_RIGHT    0x14   /* move cursor right (increment)          */
+#define LCD_MOVE_DISP_LEFT       0x18   /* shift display left                     */
+#define LCD_MOVE_DISP_RIGHT      0x1C   /* shift display right                    */
+
+/* function set: set interface data length and number of display lines */
+#define LCD_FUNCTION_4BIT_1LINE  0x20   /* 4-bit interface, single line, 5x7 dots */
+#define LCD_FUNCTION_4BIT_2LINES 0x28   /* 4-bit interface, dual line,   5x7 dots */
+#define LCD_FUNCTION_8BIT_1LINE  0x30   /* 8-bit interface, single line, 5x7 dots */
+#define LCD_FUNCTION_8BIT_2LINES 0x38   /* 8-bit interface, dual line,   5x7 dots */
+
+
+#define LCD_MODE_DEFAULT     ((1<<LCD_ENTRY_MODE) | (1<<LCD_ENTRY_INC) )
+
+
+
+/** 
+ *  @name Functions
+ */
+
+
+/**
+ @brief    Initialize display and select type of cursor
+ @param    dispAttr \b LCD_DISP_OFF display off\n
+                    \b LCD_DISP_ON display on, cursor off\n
+                    \b LCD_DISP_ON_CURSOR display on, cursor on\n
+                    \b LCD_DISP_ON_CURSOR_BLINK display on, cursor on flashing             
+ @return  none
+*/
+extern void lcd_init(uint8_t dispAttr);
+
+
+/**
+ @brief    Clear display and set cursor to home position
+ @return   none
+*/
+extern void lcd_clrscr(void);
+
+
+/**
+ @brief    Set cursor to home position
+ @return   none
+*/
+extern void lcd_home(void);
+
+
+/**
+ @brief    Set cursor to specified position
+ 
+ @param    x horizontal position\n (0: left most position)
+ @param    y vertical position\n   (0: first line)
+ @return   none
+*/
+extern void lcd_gotoxy(uint8_t x, uint8_t y);
+
+
+/**
+ @brief    Display character at current cursor position
+ @param    c character to be displayed                                       
+ @return   none
+*/
+extern void lcd_putc(char c);
+
+
+/**
+ @brief    Display string without auto linefeed
+ @param    s string to be displayed                                        
+ @return   none
+*/
+extern void lcd_puts(const char *s);
+
+
+/**
+ @brief    Display string from program memory without auto linefeed
+ @param    progmem_s string from program memory be be displayed                                        
+ @return   none
+ @see      lcd_puts_P
+*/
+extern void lcd_puts_p(const char *progmem_s);
+
+
+/**
+ @brief    Send LCD controller instruction command
+ @param    cmd instruction to send to LCD controller, see HD44780 data sheet
+ @return   none
+*/
+extern void lcd_command(uint8_t cmd);
+
+
+/**
+ @brief    Send data byte to LCD controller 
+ 
+ Similar to lcd_putc(), but without interpreting LF
+ @param    data byte to send to LCD controller, see HD44780 data sheet
+ @return   none
+*/
+extern void lcd_data(uint8_t data);
+
+
+/**
+ @brief macros for automatically storing string constant in program memory
+*/
+#define lcd_puts_P(__s)         lcd_puts_p(PSTR(__s))
+
+/**@}*/
+
+#endif //LCD_H
+

quantum/quantum.c

@@ -1187,6 +1187,10 @@ void backlight_set(uint8_t level) {}
 
 #endif // backlight
 
+#ifdef HD44780_ENABLED
+#include "hd44780.h"
+#endif
+
 
 // Functions for spitting out values
 //

quantum/quantum.h

@@ -121,6 +121,10 @@ extern uint32_t default_layer_state;
 	#include "process_terminal_nop.h"
 #endif
 
+#ifdef HD44780_ENABLE
+	#include "hd44780.h"
+#endif
+
 #define STRINGIZE(z) #z
 #define ADD_SLASH_X(y) STRINGIZE(\x ## y)
 #define SYMBOL_STR(x) ADD_SLASH_X(x)

quantum/template/avr/config.h

@@ -187,4 +187,32 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* override number of MIDI tone keycodes (each octave adds 12 keycodes and allocates 12 bytes) */
 //#define MIDI_TONE_KEYCODE_OCTAVES 1
 
+/*
+ * HD44780 LCD Display Configuration
+ */
+/*
+#define LCD_LINES           2     //< number of visible lines of the display
+#define LCD_DISP_LENGTH    16     //< visibles characters per line of the display
+
+#define LCD_IO_MODE      1            //< 0: memory mapped mode, 1: IO port mode
+
+#if LCD_IO_MODE
+#define LCD_PORT         PORTB        //< port for the LCD lines
+#define LCD_DATA0_PORT   LCD_PORT     //< port for 4bit data bit 0
+#define LCD_DATA1_PORT   LCD_PORT     //< port for 4bit data bit 1
+#define LCD_DATA2_PORT   LCD_PORT     //< port for 4bit data bit 2
+#define LCD_DATA3_PORT   LCD_PORT     //< port for 4bit data bit 3
+#define LCD_DATA0_PIN    4            //< pin for 4bit data bit 0
+#define LCD_DATA1_PIN    5            //< pin for 4bit data bit 1
+#define LCD_DATA2_PIN    6            //< pin for 4bit data bit 2 
+#define LCD_DATA3_PIN    7            //< pin for 4bit data bit 3
+#define LCD_RS_PORT      LCD_PORT     //< port for RS line        
+#define LCD_RS_PIN       3            //< pin  for RS line        
+#define LCD_RW_PORT      LCD_PORT     //< port for RW line        
+#define LCD_RW_PIN       2            //< pin  for RW line        
+#define LCD_E_PORT       LCD_PORT     //< port for Enable line     
+#define LCD_E_PIN        1            //< pin  for Enable line    
+#endif
+*/ 
+
 #endif

quantum/template/avr/rules.mk

@@ -66,3 +66,4 @@ UNICODE_ENABLE = no         # Unicode
 BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
 AUDIO_ENABLE = no           # Audio output on port C6
 FAUXCLICKY_ENABLE = no      # Use buzzer to emulate clicky switches
+HD44780_ENABLE = no 		# Enable support for HD44780 based LCDs (+400)

tmk_core/common/keyboard.c

@@ -69,6 +69,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #ifdef MIDI_ENABLE
 #   include "process_midi.h"
 #endif
+#ifdef HD44780_ENABLE
+#   include "hd44780.h"
+#endif
 
 #ifdef MATRIX_HAS_GHOST
 extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];