1 /****************************************************************************
2 Title: HD44780U LCD library
3 Author: Peter Fleury <pfleury@gmx.ch> http://tinyurl.com/peterfleury
4 License: GNU General Public License Version 3
5 File: $Id: lcd.c,v 1.15.2.2 2015/01/17 12:16:05 peter Exp $
7 Target: any AVR device, memory mapped mode only for AT90S4414/8515/Mega
10 Basic routines for interfacing a HD44780U-based text lcd display
12 Originally based on Volker Oth's lcd library,
13 changed lcd_init(), added additional constants for lcd_command(),
14 added 4-bit I/O mode, improved and optimized code.
16 Library can be operated in memory mapped mode (LCD_IO_MODE=0) or in
17 4-bit IO port mode (LCD_IO_MODE=1). 8-bit IO port mode not supported.
19 Memory mapped mode compatible with Kanda STK200, but supports also
20 generation of R/W signal through A8 address line.
23 See the C include lcd.h file for a description of each function
25 *****************************************************************************/
28 #include <avr/pgmspace.h>
29 #include <util/delay.h>
35 #define DDR(x) (*(&x - 1)) /* address of data direction register of port x */
36 #if defined(__AVR_ATmega64__) || defined(__AVR_ATmega128__)
37 /* on ATmega64/128 PINF is on port 0x00 and not 0x60 */
38 #define PIN(x) ( &PORTF==&(x) ? _SFR_IO8(0x00) : (*(&x - 2)) )
40 #define PIN(x) (*(&x - 2)) /* address of input register of port x */
45 #define lcd_e_delay() _delay_us(LCD_DELAY_ENABLE_PULSE)
46 #define lcd_e_high() LCD_E_PORT |= _BV(LCD_E_PIN);
47 #define lcd_e_low() LCD_E_PORT &= ~_BV(LCD_E_PIN);
48 #define lcd_e_toggle() toggle_e()
49 #define lcd_rw_high() LCD_RW_PORT |= _BV(LCD_RW_PIN)
50 #define lcd_rw_low() LCD_RW_PORT &= ~_BV(LCD_RW_PIN)
51 #define lcd_rs_high() LCD_RS_PORT |= _BV(LCD_RS_PIN)
52 #define lcd_rs_low() LCD_RS_PORT &= ~_BV(LCD_RS_PIN)
57 #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_4BIT_1LINE
59 #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_4BIT_2LINES
63 #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_8BIT_1LINE
65 #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_8BIT_2LINES
69 #if LCD_CONTROLLER_KS0073
72 #define KS0073_EXTENDED_FUNCTION_REGISTER_ON 0x2C /* |0|010|1100 4-bit mode, extension-bit RE = 1 */
73 #define KS0073_EXTENDED_FUNCTION_REGISTER_OFF 0x28 /* |0|010|1000 4-bit mode, extension-bit RE = 0 */
74 #define KS0073_4LINES_MODE 0x09 /* |0|000|1001 4 lines mode */
80 ** function prototypes
83 static void toggle_e(void);
91 /*************************************************************************
92 delay for a minimum of <us> microseconds
93 the number of loops is calculated at compile-time from MCU clock frequency
94 *************************************************************************/
95 #define delay(us) _delay_us(us)
99 /* toggle Enable Pin to initiate write */
100 static void toggle_e(void)
109 /*************************************************************************
110 Low-level function to write byte to LCD controller
111 Input: data byte to write to LCD
115 *************************************************************************/
117 static void lcd_write(uint8_t data,uint8_t rs)
119 unsigned char dataBits ;
122 if (rs) { /* write data (RS=1, RW=0) */
124 } else { /* write instruction (RS=0, RW=0) */
127 lcd_rw_low(); /* RW=0 write mode */
129 if ( ( &LCD_DATA0_PORT == &LCD_DATA1_PORT) && ( &LCD_DATA1_PORT == &LCD_DATA2_PORT ) && ( &LCD_DATA2_PORT == &LCD_DATA3_PORT )
130 && (LCD_DATA0_PIN == 0) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3) )
132 /* configure data pins as output */
133 DDR(LCD_DATA0_PORT) |= 0x0F;
135 /* output high nibble first */
136 dataBits = LCD_DATA0_PORT & 0xF0;
137 LCD_DATA0_PORT = dataBits |((data>>4)&0x0F);
140 /* output low nibble */
141 LCD_DATA0_PORT = dataBits | (data&0x0F);
144 /* all data pins high (inactive) */
145 LCD_DATA0_PORT = dataBits | 0x0F;
149 /* configure data pins as output */
150 DDR(LCD_DATA0_PORT) |= _BV(LCD_DATA0_PIN);
151 DDR(LCD_DATA1_PORT) |= _BV(LCD_DATA1_PIN);
152 DDR(LCD_DATA2_PORT) |= _BV(LCD_DATA2_PIN);
153 DDR(LCD_DATA3_PORT) |= _BV(LCD_DATA3_PIN);
155 /* output high nibble first */
156 LCD_DATA3_PORT &= ~_BV(LCD_DATA3_PIN);
157 LCD_DATA2_PORT &= ~_BV(LCD_DATA2_PIN);
158 LCD_DATA1_PORT &= ~_BV(LCD_DATA1_PIN);
159 LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN);
160 if(data & 0x80) LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
161 if(data & 0x40) LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
162 if(data & 0x20) LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
163 if(data & 0x10) LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
166 /* output low nibble */
167 LCD_DATA3_PORT &= ~_BV(LCD_DATA3_PIN);
168 LCD_DATA2_PORT &= ~_BV(LCD_DATA2_PIN);
169 LCD_DATA1_PORT &= ~_BV(LCD_DATA1_PIN);
170 LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN);
171 if(data & 0x08) LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
172 if(data & 0x04) LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
173 if(data & 0x02) LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
174 if(data & 0x01) LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
177 /* all data pins high (inactive) */
178 LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
179 LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
180 LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
181 LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
185 #define lcd_write(d,rs) if (rs) *(volatile uint8_t*)(LCD_IO_DATA) = d; else *(volatile uint8_t*)(LCD_IO_FUNCTION) = d;
186 /* rs==0 -> write instruction to LCD_IO_FUNCTION */
187 /* rs==1 -> write data to LCD_IO_DATA */
191 /*************************************************************************
192 Low-level function to read byte from LCD controller
193 Input: rs 1: read data
194 0: read busy flag / address counter
195 Returns: byte read from LCD controller
196 *************************************************************************/
198 static uint8_t lcd_read(uint8_t rs)
204 lcd_rs_high(); /* RS=1: read data */
206 lcd_rs_low(); /* RS=0: read busy flag */
207 lcd_rw_high(); /* RW=1 read mode */
209 if ( ( &LCD_DATA0_PORT == &LCD_DATA1_PORT) && ( &LCD_DATA1_PORT == &LCD_DATA2_PORT ) && ( &LCD_DATA2_PORT == &LCD_DATA3_PORT )
210 && ( LCD_DATA0_PIN == 0 )&& (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3) )
212 DDR(LCD_DATA0_PORT) &= 0xF0; /* configure data pins as input */
216 data = PIN(LCD_DATA0_PORT) << 4; /* read high nibble first */
219 lcd_e_delay(); /* Enable 500ns low */
223 data |= PIN(LCD_DATA0_PORT)&0x0F; /* read low nibble */
228 /* configure data pins as input */
229 DDR(LCD_DATA0_PORT) &= ~_BV(LCD_DATA0_PIN);
230 DDR(LCD_DATA1_PORT) &= ~_BV(LCD_DATA1_PIN);
231 DDR(LCD_DATA2_PORT) &= ~_BV(LCD_DATA2_PIN);
232 DDR(LCD_DATA3_PORT) &= ~_BV(LCD_DATA3_PIN);
234 /* read high nibble first */
238 if ( PIN(LCD_DATA0_PORT) & _BV(LCD_DATA0_PIN) ) data |= 0x10;
239 if ( PIN(LCD_DATA1_PORT) & _BV(LCD_DATA1_PIN) ) data |= 0x20;
240 if ( PIN(LCD_DATA2_PORT) & _BV(LCD_DATA2_PIN) ) data |= 0x40;
241 if ( PIN(LCD_DATA3_PORT) & _BV(LCD_DATA3_PIN) ) data |= 0x80;
244 lcd_e_delay(); /* Enable 500ns low */
246 /* read low nibble */
249 if ( PIN(LCD_DATA0_PORT) & _BV(LCD_DATA0_PIN) ) data |= 0x01;
250 if ( PIN(LCD_DATA1_PORT) & _BV(LCD_DATA1_PIN) ) data |= 0x02;
251 if ( PIN(LCD_DATA2_PORT) & _BV(LCD_DATA2_PIN) ) data |= 0x04;
252 if ( PIN(LCD_DATA3_PORT) & _BV(LCD_DATA3_PIN) ) data |= 0x08;
258 #define lcd_read(rs) (rs) ? *(volatile uint8_t*)(LCD_IO_DATA+LCD_IO_READ) : *(volatile uint8_t*)(LCD_IO_FUNCTION+LCD_IO_READ)
259 /* rs==0 -> read instruction from LCD_IO_FUNCTION */
260 /* rs==1 -> read data from LCD_IO_DATA */
264 /*************************************************************************
265 loops while lcd is busy, returns address counter
266 *************************************************************************/
267 static uint8_t lcd_waitbusy(void)
272 /* wait until busy flag is cleared */
273 while ( (c=lcd_read(0)) & (1<<LCD_BUSY)) {}
275 /* the address counter is updated 4us after the busy flag is cleared */
276 delay(LCD_DELAY_BUSY_FLAG);
278 /* now read the address counter */
279 return (lcd_read(0)); // return address counter
284 /*************************************************************************
285 Move cursor to the start of next line or to the first line if the cursor
286 is already on the last line.
287 *************************************************************************/
288 static inline void lcd_newline(uint8_t pos)
290 register uint8_t addressCounter;
297 if ( pos < (LCD_START_LINE2) )
298 addressCounter = LCD_START_LINE2;
300 addressCounter = LCD_START_LINE1;
303 #if KS0073_4LINES_MODE
304 if ( pos < LCD_START_LINE2 )
305 addressCounter = LCD_START_LINE2;
306 else if ( (pos >= LCD_START_LINE2) && (pos < LCD_START_LINE3) )
307 addressCounter = LCD_START_LINE3;
308 else if ( (pos >= LCD_START_LINE3) && (pos < LCD_START_LINE4) )
309 addressCounter = LCD_START_LINE4;
311 addressCounter = LCD_START_LINE1;
313 if ( pos < LCD_START_LINE3 )
314 addressCounter = LCD_START_LINE2;
315 else if ( (pos >= LCD_START_LINE2) && (pos < LCD_START_LINE4) )
316 addressCounter = LCD_START_LINE3;
317 else if ( (pos >= LCD_START_LINE3) && (pos < LCD_START_LINE2) )
318 addressCounter = LCD_START_LINE4;
320 addressCounter = LCD_START_LINE1;
323 lcd_command((1<<LCD_DDRAM)+addressCounter);
332 /*************************************************************************
333 Send LCD controller instruction command
334 Input: instruction to send to LCD controller, see HD44780 data sheet
336 *************************************************************************/
337 void lcd_command(uint8_t cmd)
344 /*************************************************************************
345 Send data byte to LCD controller
346 Input: data to send to LCD controller, see HD44780 data sheet
348 *************************************************************************/
349 void lcd_data(uint8_t data)
357 /*************************************************************************
358 Set cursor to specified position
359 Input: x horizontal position (0: left most position)
360 y vertical position (0: first line)
362 *************************************************************************/
363 void lcd_gotoxy(uint8_t x, uint8_t y)
366 lcd_command((1<<LCD_DDRAM)+LCD_START_LINE1+x);
370 lcd_command((1<<LCD_DDRAM)+LCD_START_LINE1+x);
372 lcd_command((1<<LCD_DDRAM)+LCD_START_LINE2+x);
376 lcd_command((1<<LCD_DDRAM)+LCD_START_LINE1+x);
378 lcd_command((1<<LCD_DDRAM)+LCD_START_LINE2+x);
380 lcd_command((1<<LCD_DDRAM)+LCD_START_LINE3+x);
382 lcd_command((1<<LCD_DDRAM)+LCD_START_LINE4+x);
388 /*************************************************************************
389 *************************************************************************/
392 return lcd_waitbusy();
396 /*************************************************************************
397 Clear display and set cursor to home position
398 *************************************************************************/
399 void lcd_clrscr(void)
401 lcd_command(1<<LCD_CLR);
405 /*************************************************************************
406 Set cursor to home position
407 *************************************************************************/
410 lcd_command(1<<LCD_HOME);
414 /*************************************************************************
415 Display character at current cursor position
416 Input: character to be displayed
418 *************************************************************************/
419 void lcd_putc(char c)
424 pos = lcd_waitbusy(); // read busy-flag and address counter
431 #if LCD_WRAP_LINES==1
433 if ( pos == LCD_START_LINE1+LCD_DISP_LENGTH ) {
434 lcd_write((1<<LCD_DDRAM)+LCD_START_LINE1,0);
437 if ( pos == LCD_START_LINE1+LCD_DISP_LENGTH ) {
438 lcd_write((1<<LCD_DDRAM)+LCD_START_LINE2,0);
439 }else if ( pos == LCD_START_LINE2+LCD_DISP_LENGTH ){
440 lcd_write((1<<LCD_DDRAM)+LCD_START_LINE1,0);
443 if ( pos == LCD_START_LINE1+LCD_DISP_LENGTH ) {
444 lcd_write((1<<LCD_DDRAM)+LCD_START_LINE2,0);
445 }else if ( pos == LCD_START_LINE2+LCD_DISP_LENGTH ) {
446 lcd_write((1<<LCD_DDRAM)+LCD_START_LINE3,0);
447 }else if ( pos == LCD_START_LINE3+LCD_DISP_LENGTH ) {
448 lcd_write((1<<LCD_DDRAM)+LCD_START_LINE4,0);
449 }else if ( pos == LCD_START_LINE4+LCD_DISP_LENGTH ) {
450 lcd_write((1<<LCD_DDRAM)+LCD_START_LINE1,0);
461 /*************************************************************************
462 Display string without auto linefeed
463 Input: string to be displayed
465 *************************************************************************/
466 void lcd_puts(const char *s)
467 /* print string on lcd (no auto linefeed) */
471 while ( (c = *s++) ) {
478 /*************************************************************************
479 Display string from program memory without auto linefeed
480 Input: string from program memory be be displayed
482 *************************************************************************/
483 void lcd_puts_p(const char *progmem_s)
484 /* print string from program memory on lcd (no auto linefeed) */
488 while ( (c = pgm_read_byte(progmem_s++)) ) {
495 /*************************************************************************
496 Initialize display and select type of cursor
497 Input: dispAttr LCD_DISP_OFF display off
498 LCD_DISP_ON display on, cursor off
499 LCD_DISP_ON_CURSOR display on, cursor on
500 LCD_DISP_CURSOR_BLINK display on, cursor on flashing
502 *************************************************************************/
503 void lcd_init(uint8_t dispAttr)
507 * Initialize LCD to 4 bit I/O mode
510 if ( ( &LCD_DATA0_PORT == &LCD_DATA1_PORT) && ( &LCD_DATA1_PORT == &LCD_DATA2_PORT ) && ( &LCD_DATA2_PORT == &LCD_DATA3_PORT )
511 && ( &LCD_RS_PORT == &LCD_DATA0_PORT) && ( &LCD_RW_PORT == &LCD_DATA0_PORT) && (&LCD_E_PORT == &LCD_DATA0_PORT)
512 && (LCD_DATA0_PIN == 0 ) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3)
513 && (LCD_RS_PIN == 4 ) && (LCD_RW_PIN == 5) && (LCD_E_PIN == 6 ) )
515 /* configure all port bits as output (all LCD lines on same port) */
516 DDR(LCD_DATA0_PORT) |= 0x7F;
518 else if ( ( &LCD_DATA0_PORT == &LCD_DATA1_PORT) && ( &LCD_DATA1_PORT == &LCD_DATA2_PORT ) && ( &LCD_DATA2_PORT == &LCD_DATA3_PORT )
519 && (LCD_DATA0_PIN == 0 ) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3) )
521 /* configure all port bits as output (all LCD data lines on same port, but control lines on different ports) */
522 DDR(LCD_DATA0_PORT) |= 0x0F;
523 DDR(LCD_RS_PORT) |= _BV(LCD_RS_PIN);
524 DDR(LCD_RW_PORT) |= _BV(LCD_RW_PIN);
525 DDR(LCD_E_PORT) |= _BV(LCD_E_PIN);
529 /* configure all port bits as output (LCD data and control lines on different ports */
530 DDR(LCD_RS_PORT) |= _BV(LCD_RS_PIN);
531 DDR(LCD_RW_PORT) |= _BV(LCD_RW_PIN);
532 DDR(LCD_E_PORT) |= _BV(LCD_E_PIN);
533 DDR(LCD_DATA0_PORT) |= _BV(LCD_DATA0_PIN);
534 DDR(LCD_DATA1_PORT) |= _BV(LCD_DATA1_PIN);
535 DDR(LCD_DATA2_PORT) |= _BV(LCD_DATA2_PIN);
536 DDR(LCD_DATA3_PORT) |= _BV(LCD_DATA3_PIN);
538 delay(LCD_DELAY_BOOTUP); /* wait 16ms or more after power-on */
540 /* initial write to lcd is 8bit */
541 LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN); // LCD_FUNCTION>>4;
542 LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN); // LCD_FUNCTION_8BIT>>4;
544 delay(LCD_DELAY_INIT); /* delay, busy flag can't be checked here */
546 /* repeat last command */
548 delay(LCD_DELAY_INIT_REP); /* delay, busy flag can't be checked here */
550 /* repeat last command a third time */
552 delay(LCD_DELAY_INIT_REP); /* delay, busy flag can't be checked here */
554 /* now configure for 4bit mode */
555 LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN); // LCD_FUNCTION_4BIT_1LINE>>4
557 delay(LCD_DELAY_INIT_4BIT); /* some displays need this additional delay */
559 /* from now the LCD only accepts 4 bit I/O, we can use lcd_command() */
562 * Initialize LCD to 8 bit memory mapped mode
565 /* enable external SRAM (memory mapped lcd) and one wait state */
566 MCUCR = _BV(SRE) | _BV(SRW);
569 delay(LCD_DELAY_BOOTUP); /* wait 16ms after power-on */
570 lcd_write(LCD_FUNCTION_8BIT_1LINE,0); /* function set: 8bit interface */
571 delay(LCD_DELAY_INIT); /* wait 5ms */
572 lcd_write(LCD_FUNCTION_8BIT_1LINE,0); /* function set: 8bit interface */
573 delay(LCD_DELAY_INIT_REP); /* wait 64us */
574 lcd_write(LCD_FUNCTION_8BIT_1LINE,0); /* function set: 8bit interface */
575 delay(LCD_DELAY_INIT_REP); /* wait 64us */
578 #if KS0073_4LINES_MODE
579 /* Display with KS0073 controller requires special commands for enabling 4 line mode */
580 lcd_command(KS0073_EXTENDED_FUNCTION_REGISTER_ON);
581 lcd_command(KS0073_4LINES_MODE);
582 lcd_command(KS0073_EXTENDED_FUNCTION_REGISTER_OFF);
584 lcd_command(LCD_FUNCTION_DEFAULT); /* function set: display lines */
586 lcd_command(LCD_DISP_OFF); /* display off */
587 lcd_clrscr(); /* display clear */
588 lcd_command(LCD_MODE_DEFAULT); /* set entry mode */
589 lcd_command(dispAttr); /* display/cursor control */