avr/display/display.h

/*
Copyright 2022, Savanni D'Gerinel <savanni@luminescent-dreams.com>

This file is part of Savanni's AVR library.

Lumeto 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.

Lumeto 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 Lumeto. If not, see <https://www.gnu.org/licenses/>.
*/

/* This library covers a five-wire diagnostic display board.
 *
 * Hardware:
 * 74HC595 shift register
 * Adafruit HD44780 LCD
 *
 * Input pins:
 *  SDI -- Serial data in. This leads to the 74HC595, pin 14 (A).
 *  CLK -- Clock pulse. One bit will be shifted into the device on each rising
 *    edge. This leads to the 74HC595, pin 11 (Shift Clock).
 *  LS -- Latch pulse. All data in the shift register will be sent to the
 *    output on a rising edge. This leads to the 74HC595, pin 12 (Latch Clock);
 *  RS -- Register select. 0 to write an instruction to the display, 1 to write
 *    data to the display.
 *  E -- Enable. This tells the display to read the data. The display will get
 *    the data on the shift register outputs, so be sure to send LS before
 *    sending E.
 *
 * 74HC595 -> HD44780
 *  Qa -> D0
 *  Qb -> D1
 *  Qc -> D2
 *  Qd -> D3
 *  Qe -> D4
 *  Qf -> D5
 *  Qg -> D6
 *  Qh -> D7
 */

#ifndef __DISPLAY_H__
#define __DISPLAY_H__

#include <shift_register.h>

typedef struct DISPLAY {
    shift_register_t reg;
    gpio_t register_select;
    gpio_t enable;
} display_t;

void display_init(display_t *);

void display_clear(display_t *);

void display_enable(display_t *);

void display_set_location(display_t *, size_t, size_t);

void display_write_message(display_t *, const char *);

#endif