/*##############################################################*/ /* Author: Marcus Nasarek */ /* File: LCDH44780.c */ /* Compile with: */ /* gcc -Wall -c LCDHD44780.c -o LCDHD44780.o */ /* License: */ /* */ /* This program is free software; you can redistribute it */ /* and/or modify it under the terms of the GNU General */ /* Public License as published by the Free Software */ /* Foundation; either version 3 of the License, or */ /* (at your option) any later version. */ /* */ /* This program is distributed in the hope that it will */ /* be useful, but WITHOUT ANY WARRANTY; without even the */ /* implied warranty of MERCHANTABILITY or */ /* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General */ /* Public License for more details. */ /* */ /* You should have received a copy of the GNU General */ /* Public License along with this program; if not, */ /* see . */ /* */ /*##############################################################*/ #include "LCDHD44780.h" void init_gpio(void) { // Set all pins to output bcm2835_gpio_fsel(LCD_RS, BCM2835_GPIO_FSEL_OUTP); bcm2835_gpio_fsel(LCD_D4, BCM2835_GPIO_FSEL_OUTP); bcm2835_gpio_fsel(LCD_D5, BCM2835_GPIO_FSEL_OUTP); bcm2835_gpio_fsel(LCD_D6, BCM2835_GPIO_FSEL_OUTP); bcm2835_gpio_fsel(LCD_D7, BCM2835_GPIO_FSEL_OUTP); bcm2835_gpio_fsel(LCD_E, BCM2835_GPIO_FSEL_OUTP); bcm2835_delayMicroseconds(C_DELAY); // Set all pins to LOW bcm2835_gpio_clr(LCD_RS); bcm2835_gpio_clr(LCD_D4); bcm2835_gpio_clr(LCD_D5); bcm2835_gpio_clr(LCD_D5); bcm2835_gpio_clr(LCD_D7); bcm2835_gpio_clr(LCD_E); } void pulse_e(void) { // Toogle ENABLE pin in us // bcm2835_gpio_fsel(LCD_E, BCM2835_GPIO_FSEL_OUTP); bcm2835_delayMicroseconds(E_DELAY); bcm2835_gpio_set(LCD_E); bcm2835_delayMicroseconds(E_DATA_PULSE); bcm2835_gpio_clr(LCD_E); (LCD_DATA) ? bcm2835_delayMicroseconds(E_DATA_PULSE) :bcm2835_delayMicroseconds(E_CMD_PULSE); } void init_lcd(void) { init_gpio(); /* The busy flag (BF) is kept in the busy state until the initialization ends (BF = 1). The busy state lasts for 10 ms after VCC rises to 4.5 V */ /* --- symbols: I/D = 1: Increment I/D = 0: Decrement S = 1: Accompanies display shift S/C = 1: Display shift S/C = 0: Cursor move R/L = 1: Shift to the right R/L = 0: Shift to the left DL = 1: 8 bits, DL = 0: 4 bits N = 1: 2 lines, N = 0: 1 line F = 1: 5 × 10 dots, F = 0: 5 × 8 dots BF = 1: Internally operating BF = 0: Instructions acceptable */ /* --- Display init after turn on: 1. Display clear 2. Function set: DL = 1; 8-bit interface data N = 0; 1-line display F = 0; 5×8 dot character font 3. Display on/off control: D = 0; Display off C = 0; Cursor off B = 0; Blinking off 4. Entry mode set: I/D = 1; Increment by 1 S = 0; No shift */ // begin of "warming up" // see fig 24 on page 46 of datasheet // Function set - // Sets interface data length // (DL), number of display lines // (N), and character font (F). // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 1 DL N F - - // DL = 0 --> 4 bit data length (1 = 8 bit) // N = 1 --> 2 line display (0 = 1 line) // F = 0 --> 5x8 dot character font // 0x33 = // 0 0 0 0 1 1 0 0 1 1 // --> ? write_to_lcd(0x33, LCD_CMD); bcm2835_delayMicroseconds(100); // Function set - // Sets interface data length // (DL), number of display lines // (N), and character font (F). // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 1 DL N F - - // DL = 0 --> 4 bit data length (1 = 8 bit) // N = 1 --> 2 line display (0 = 1 line) // F = 0 --> 5x8 dot character font // 0x32 = // 0 0 0 0 1 1 0 0 1 0 // --> ? write_to_lcd(0x32, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); // end of "warming up" lcd_function_set(TWO_LINES); lcd_control(DISPLAY_ON); lcd_entry_mode(ADDR_INCREMENT); clear_lcd(); } void lcd_function_set(uint8_t control_flags) { // Function set - // Sets interface data length // (DL), number of display lines // (N), and character font (F). // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 1 DL N F - - // DL = 0 --> 4 bit data length (1 = 8 bit) // N = 1 --> 2 line display (0 = 1 line) // F = 0 --> 5x8 dot character font // F = 1 --> 5x10 dot character font // 0x28 = // 0 0 0 0 1 0 1 0 0 0 write_to_lcd(LCD_FUNCTION_SET | control_flags, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); } void lcd_control(uint8_t control_flags) { // Display on/off control - // Sets entire display (D) on/off, // cursor on/off (C), and // blinking of cursor position // character (B). // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 0 0 1 D C B // D = 1 --> display on // C = 0 --> cursor off // B = 0 --> blinking off write_to_lcd(LCD_CONTROL | control_flags, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); } void lcd_shift_control(uint8_t control_flags) { // Cursor or display shift - // Moves the cursor and shifts // display without chaning // DDRAM contents. // Execution time 37us // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 0 1 S/C R/L - - // S/C = cursor/display shift // S/C = 0 --> cursor shift // R/L = shift direction // R/L = 1 --> shift to right write_to_lcd(CURSOR_DISPLAY_SHIFT | control_flags, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); } void lcd_entry_mode(uint8_t control_flags) { // Entry mode set - // Sets cursor move direction // and specifies display shift. // These operations are // performed during data write // and read. // Execution time 37us // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 0 0 0 1 I/D S // I/D = increment/decrement address pointer // I/D = 1 --> increment // S = 0 --> no shift write_to_lcd(LCD_ENTRY_MODE | control_flags, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); } void clear_lcd(void) { // Clear display - // Clears entire display and // sets DDRAM address 0 in // address counter: // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 0 0 0 0 0 1 write_to_lcd(0x01, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); } void return_home(void) { // Return home - // Sets DDRAM address to 0 // in address counter. Also // returns display from being // shifted to original position // DDRAM contents remains unchanged // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 0 0 0 0 0 0 1 - write_to_lcd(0x02, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); } void display_off(void) { lcd_control(DISPLAY_OFF); } void show_cursor(bool on) { uint8_t cursor_flag; cursor_flag = ( on ? CURSOR_ON : 0x00); lcd_control(DISPLAY_ON | cursor_flag); } void cursor_blinking(bool on) { uint8_t blinking_flag; blinking_flag = ( on ? BLINKING_ON : 0x00); lcd_control(DISPLAY_ON | blinking_flag); } void set_cursor(uint8_t addr) { // Set DDRAM address // RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 // 0 0 1 ADD ADD ADD ADD ADD ADD ADD write_to_lcd(addr, LCD_CMD); bcm2835_delayMicroseconds(R_EXEC_TIME); // fprintf(stdout,"cursor on addr: 0x%0x\n", addr); } void shift_cursor(uint8_t direction) { lcd_shift_control(CURSOR_SHIFT | direction); } void shift_display(uint8_t direction) { lcd_shift_control(DISPLAY_SHIFT | direction); } void write_to_lcd(uint8_t byte, uint8_t mode) { switch (mode) { case LCD_CMD: bcm2835_gpio_clr(LCD_RS); // fprintf(stdout, "Set RS to cmd mode\n"); break; case LCD_DATA: bcm2835_gpio_set(LCD_RS); // fprintf(stdout, "Set RS to data mode for '%c'\n", byte); break; default: // fprintf(stderr, "mode for setting GPIO pin unknown: %i\n", mode); exit(EXIT_FAILURE); } // write high bits bcm2835_gpio_clr(LCD_D4); bcm2835_gpio_clr(LCD_D5); bcm2835_gpio_clr(LCD_D6); bcm2835_gpio_clr(LCD_D7); if ((byte & 0x10) == 0x10) { bcm2835_gpio_set(LCD_D4); } if ((byte & 0x20) == 0x20) { bcm2835_gpio_set(LCD_D5); } if ((byte & 0x40) == 0x40) { bcm2835_gpio_set(LCD_D6); } if ((byte & 0x80) == 0x80) { bcm2835_gpio_set(LCD_D7); } // Toogle ENABLE pin in us pulse_e(); // write low bits bcm2835_gpio_clr(LCD_D4); bcm2835_gpio_clr(LCD_D5); bcm2835_gpio_clr(LCD_D6); bcm2835_gpio_clr(LCD_D7); if ((byte & 0x01) == 0x01) { bcm2835_gpio_set(LCD_D4); } if ((byte & 0x02) == 0x02) { bcm2835_gpio_set(LCD_D5); } if ((byte & 0x04) == 0x04) { bcm2835_gpio_set(LCD_D6); } if ((byte & 0x08) == 0x08) { bcm2835_gpio_set(LCD_D7); } pulse_e(); } void write_string(char *str) { uint16_t i; uint8_t len = 0; len = (strlen(str) > LCD_WIDTH ? LCD_WIDTH : strlen(str)); for (i=0; i