284 lines
7 KiB
C
284 lines
7 KiB
C
/*
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Copyright 2022
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "hd44780.h"
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#include "gpio.h"
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#include "progmem.h"
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#include "wait.h"
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#ifndef HD44780_DATA_PINS
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# error hd44780: no data pins defined!
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#endif
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#ifndef HD44780_RS_PIN
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# error hd44780: no RS pin defined!
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#endif
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#ifndef HD44780_RW_PIN
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# error hd44780: no R/W pin defined!
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#endif
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#ifndef HD44780_E_PIN
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# error hd44780: no E pin defined!
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#endif
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static const pin_t data_pins[4] = HD44780_DATA_PINS;
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#ifndef HD44780_DISPLAY_COLS
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# define HD44780_DISPLAY_COLS 16
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#endif
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#ifndef HD44780_DISPLAY_LINES
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# define HD44780_DISPLAY_LINES 2
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#endif
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#ifndef HD44780_DDRAM_LINE0_ADDR
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# define HD44780_DDRAM_LINE0_ADDR 0x00
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#endif
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#ifndef HD44780_DDRAM_LINE1_ADDR
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# define HD44780_DDRAM_LINE1_ADDR 0x40
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#endif
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#define HD44780_INIT_DELAY_MS 16
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#define HD44780_ENABLE_DELAY_US 1
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static void hd44780_latch(void) {
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gpio_write_pin_high(HD44780_E_PIN);
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wait_us(HD44780_ENABLE_DELAY_US);
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gpio_write_pin_low(HD44780_E_PIN);
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}
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void hd44780_write(uint8_t data, bool isData) {
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gpio_write_pin(HD44780_RS_PIN, isData);
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gpio_write_pin_low(HD44780_RW_PIN);
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for (int i = 0; i < 4; i++) {
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gpio_set_pin_output(data_pins[i]);
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}
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// Write high nibble
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for (int i = 0; i < 4; i++) {
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gpio_write_pin(data_pins[i], (data >> 4) & (1 << i));
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}
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hd44780_latch();
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// Write low nibble
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for (int i = 0; i < 4; i++) {
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gpio_write_pin(data_pins[i], data & (1 << i));
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}
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hd44780_latch();
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for (int i = 0; i < 4; i++) {
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gpio_write_pin_high(data_pins[i]);
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}
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}
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uint8_t hd44780_read(bool isData) {
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uint8_t data = 0;
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gpio_write_pin(HD44780_RS_PIN, isData);
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gpio_write_pin_high(HD44780_RW_PIN);
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for (int i = 0; i < 4; i++) {
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gpio_set_pin_input(data_pins[i]);
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}
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gpio_write_pin_high(HD44780_E_PIN);
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wait_us(HD44780_ENABLE_DELAY_US);
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// Read high nibble
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for (int i = 0; i < 4; i++) {
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data |= (gpio_read_pin(data_pins[i]) << i);
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}
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data <<= 4;
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gpio_write_pin_low(HD44780_E_PIN);
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wait_us(HD44780_ENABLE_DELAY_US);
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gpio_write_pin_high(HD44780_E_PIN);
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wait_us(HD44780_ENABLE_DELAY_US);
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// Read low nibble
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for (int i = 0; i < 4; i++) {
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data |= (gpio_read_pin(data_pins[i]) << i);
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}
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gpio_write_pin_low(HD44780_E_PIN);
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return data;
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}
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bool hd44780_busy(void) {
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return hd44780_read(false) & HD44780_BUSY_FLAG;
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}
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void hd44780_command(uint8_t command) {
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while (hd44780_busy())
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;
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hd44780_write(command, false);
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}
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void hd44780_data(uint8_t data) {
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while (hd44780_busy())
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;
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hd44780_write(data, true);
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}
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void hd44780_clear(void) {
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hd44780_command(HD44780_CMD_CLEAR_DISPLAY);
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}
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void hd44780_home(void) {
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hd44780_command(HD44780_CMD_RETURN_HOME);
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}
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void hd44780_on(bool cursor, bool blink) {
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if (cursor) {
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if (blink) {
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hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON | HD44780_DISPLAY_CURSOR | HD44780_DISPLAY_BLINK);
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} else {
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hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON | HD44780_DISPLAY_CURSOR);
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}
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} else {
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hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON);
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}
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}
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void hd44780_off(void) {
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hd44780_command(HD44780_CMD_DISPLAY);
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}
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void hd44780_set_cgram_address(uint8_t address) {
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hd44780_command(HD44780_CMD_SET_CGRAM_ADDRESS + (address & 0x3F));
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}
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void hd44780_set_ddram_address(uint8_t address) {
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hd44780_command(HD44780_CMD_SET_DDRAM_ADDRESS + (address & 0x7F));
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}
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void hd44780_init(bool cursor, bool blink) {
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gpio_set_pin_output(HD44780_RS_PIN);
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gpio_set_pin_output(HD44780_RW_PIN);
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gpio_set_pin_output(HD44780_E_PIN);
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for (int i = 0; i < 4; i++) {
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gpio_set_pin_output(data_pins[i]);
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}
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wait_ms(HD44780_INIT_DELAY_MS);
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// Manually configure for 4-bit mode - can't use hd44780_command() yet
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// HD44780U datasheet, Fig. 24 (p46)
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gpio_write_pin_high(data_pins[0]); // Function set
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gpio_write_pin_high(data_pins[1]); // DL = 1
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hd44780_latch();
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wait_ms(5);
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// Send again
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hd44780_latch();
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wait_us(64);
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// And again (?)
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hd44780_latch();
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wait_us(64);
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gpio_write_pin_low(data_pins[0]); // DL = 0
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hd44780_latch();
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wait_us(64);
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#if HD44780_DISPLAY_LINES == 1
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hd44780_command(HD44780_CMD_FUNCTION); // 4 bit, 1 line, 5x8 dots
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#else
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hd44780_command(HD44780_CMD_FUNCTION | HD44780_FUNCTION_2_LINES); // 4 bit, 2 lines, 5x8 dots
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#endif
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hd44780_on(cursor, blink);
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hd44780_clear();
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hd44780_home();
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hd44780_command(HD44780_CMD_ENTRY_MODE | HD44780_ENTRY_MODE_INC);
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}
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void hd44780_set_cursor(uint8_t col, uint8_t line) {
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register uint8_t address = col;
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#if HD44780_DISPLAY_LINES == 1
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address += HD44780_DDRAM_LINE0_ADDR;
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#elif HD44780_DISPLAY_LINES == 2
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if (line == 0) {
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address += HD44780_DDRAM_LINE0_ADDR;
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} else {
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address += HD44780_DDRAM_LINE1_ADDR;
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}
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#endif
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hd44780_set_ddram_address(address);
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}
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void hd44780_define_char(uint8_t index, uint8_t *data) {
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hd44780_set_cgram_address((index & 0x7) << 3);
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for (uint8_t i = 0; i < 8; i++) {
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hd44780_data(data[i]);
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}
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}
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void hd44780_putc(char c) {
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while (hd44780_busy())
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;
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uint8_t current_position = hd44780_read(false);
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if (c == '\n') {
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hd44780_set_cursor(0, current_position < HD44780_DDRAM_LINE1_ADDR ? 1 : 0);
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} else {
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#if defined(HD44780_WRAP_LINES)
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# if HD44780_DISPLAY_LINES == 1
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if (current_position == HD44780_DDRAM_LINE0_ADDR + HD44780_DISPLAY_COLS) {
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// Go to start of line
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hd44780_set_cursor(0, 0);
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}
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# elif HD44780_DISPLAY_LINES == 2
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if (current_position == HD44780_DDRAM_LINE0_ADDR + HD44780_DISPLAY_COLS) {
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// Go to start of second line
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hd44780_set_cursor(0, 1);
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} else if (current_position == HD44780_DDRAM_LINE1_ADDR + HD44780_DISPLAY_COLS) {
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// Go to start of first line
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hd44780_set_cursor(0, 0);
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}
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# endif
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#endif
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hd44780_data(c);
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}
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}
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void hd44780_puts(const char *s) {
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register char c;
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while ((c = *s++)) {
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hd44780_putc(c);
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}
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}
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#if defined(__AVR__)
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void hd44780_define_char_P(uint8_t index, const uint8_t *data) {
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hd44780_set_cgram_address(index << 3);
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for (uint8_t i = 0; i < 8; i++) {
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hd44780_data(pgm_read_byte(data++));
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}
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}
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void hd44780_puts_P(const char *s) {
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register char c;
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while ((c = pgm_read_byte(s++))) {
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hd44780_putc(c);
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}
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}
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#endif
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