rpi4b-temp-humidity/src/lcd.h

/*
 * lcd.h - Subroutines for communicating with HD44780U based LCD panels
 * Copyright (C) 2024  Alexander Rosenberg
 *
 * 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. See the LICENSE file for more information.
 */
#ifndef INCLUDED_LCD_H
#define INCLUDED_LCD_H

#include <sys/types.h>
#include <libgpio.h>
#include <stdbool.h>

typedef struct {
    gpio_handle_t handle;
    // pin numbers
    gpio_pin_t rs; // register select
    gpio_pin_t rw; // read-write
    gpio_pin_t en; // enable
    gpio_pin_t d0;
    gpio_pin_t d1;
    gpio_pin_t d2;
    gpio_pin_t d3;
    gpio_pin_t d4;
    gpio_pin_t d5;
    gpio_pin_t d6;
    gpio_pin_t d7;

    // gpio_value_ternal use
    bool is_read;
} LCD;

/*
 * Allocate and initialize a new LCD object and return a pogpio_value_ter to it. HANDLE
 * is a gpio_handle_t, each of the other arguments corresponds to the GPIO pin
 * number that the given controller pin is connected to: "register select",
 * "read-write", "enable", and data pins 0-7.
 * Return: the newly created object.
 */
LCD *lcd_open(gpio_handle_t handle, gpio_pin_t rs, gpio_pin_t rw, gpio_pin_t en,
              gpio_pin_t d0, gpio_pin_t d1, gpio_pin_t d2, gpio_pin_t d3,
              gpio_pin_t d4, gpio_pin_t d5, gpio_pin_t d6, gpio_pin_t d7);
/*
 * Close LCD by freeing any resources associated with it.
 */
void lcd_close(LCD *lcd);
/*
 * Call a single instruction on LCD. Each argument is the value of that pin.
 */
void lcd_call(LCD *lcd, gpio_value_t rs, gpio_value_t d0, gpio_value_t d1,
              gpio_value_t d2, gpio_value_t d3, gpio_value_t d4,
              gpio_value_t d5, gpio_value_t d6, gpio_value_t d7);
/*
 * Write character C to LCD.
 */
void lcd_write_char(LCD *lcd, char c);

/*
 * Write STR to LCD.
 * Return: the number of characters written.
 */
size_t lcd_write_string(LCD *lcd, const char *str);

/*
 * Move the cursor to COL on LINE, which both start from 0.
 */
void lcd_move_to(LCD *lcd, gpio_value_t line, gpio_value_t col);

/*
 * Clear LCD and return the cursor to the top right.
 */
void lcd_clear(LCD *lcd);

#define LCD_DISPLAY_ON 1
#define LCD_DISPLAY_OFF 0
#define LCD_CURSOR_ON 1
#define LCD_CURSOR_OFF 0
#define LCD_CURSOR_BLINK 1
#define LCD_CURSOR_NO_BLINK 0
/*
 * Control B, cursor blink, C, cursor visibility, and D, display power for LCD.
 */
void lcd_display_control(LCD *lcd, gpio_value_t b, gpio_value_t c, gpio_value_t d);

#define LCD_INCREMENT 1
#define LCD_DECREMENT 0
#define LCD_DISPLAY_SHIFT 1
#define LCD_CURSOR_MOVE 0
#define LCD_SHIFT_RIGHT 1
#define LCD_SHIFT_LEFT 0
/*
 * Control shift and increment for LCD.
 */
void lcd_entry_mode(LCD *lcd, gpio_value_t id, gpio_value_t s);

/*
 * Control direction and shift/move for cursor for LCD.
 */
void lcd_cursor_shift(LCD *lcd, gpio_value_t sc, gpio_value_t rl);

/*
 * Return: weather the busy flag is set for LCD.
 */
bool lcd_is_busy(LCD *lcd);

#endif