opensteno_qmk/drivers/lcd/hd44780.c
2022-03-19 17:57:22 +11:00

284 lines
6.8 KiB
C

/*
Copyright 2022
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 2 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 <http://www.gnu.org/licenses/>.
*/
#include "hd44780.h"
#include "gpio.h"
#include "progmem.h"
#include "wait.h"
#ifndef HD44780_DATA_PINS
# error hd44780: no data pins defined!
#endif
#ifndef HD44780_RS_PIN
# error hd44780: no RS pin defined!
#endif
#ifndef HD44780_RW_PIN
# error hd44780: no R/W pin defined!
#endif
#ifndef HD44780_E_PIN
# error hd44780: no E pin defined!
#endif
static const pin_t data_pins[4] = HD44780_DATA_PINS;
#ifndef HD44780_DISPLAY_COLS
# define HD44780_DISPLAY_COLS 16
#endif
#ifndef HD44780_DISPLAY_LINES
# define HD44780_DISPLAY_LINES 2
#endif
#ifndef HD44780_DDRAM_LINE0_ADDR
# define HD44780_DDRAM_LINE0_ADDR 0x00
#endif
#ifndef HD44780_DDRAM_LINE1_ADDR
# define HD44780_DDRAM_LINE1_ADDR 0x40
#endif
#define HD44780_INIT_DELAY_MS 16
#define HD44780_ENABLE_DELAY_US 1
static void hd44780_latch(void) {
writePinHigh(HD44780_E_PIN);
wait_us(HD44780_ENABLE_DELAY_US);
writePinLow(HD44780_E_PIN);
}
void hd44780_write(uint8_t data, bool isData) {
writePin(HD44780_RS_PIN, isData);
writePinLow(HD44780_RW_PIN);
for (int i = 0; i < 4; i++) {
setPinOutput(data_pins[i]);
}
// Write high nibble
for (int i = 0; i < 4; i++) {
writePin(data_pins[i], (data >> 4) & (1 << i));
}
hd44780_latch();
// Write low nibble
for (int i = 0; i < 4; i++) {
writePin(data_pins[i], data & (1 << i));
}
hd44780_latch();
for (int i = 0; i < 4; i++) {
writePinHigh(data_pins[i]);
}
}
uint8_t hd44780_read(bool isData) {
uint8_t data = 0;
writePin(HD44780_RS_PIN, isData);
writePinHigh(HD44780_RW_PIN);
for (int i = 0; i < 4; i++) {
setPinInput(data_pins[i]);
}
writePinHigh(HD44780_E_PIN);
wait_us(HD44780_ENABLE_DELAY_US);
// Read high nibble
for (int i = 0; i < 4; i++) {
data |= (readPin(data_pins[i]) << i);
}
data <<= 4;
writePinLow(HD44780_E_PIN);
wait_us(HD44780_ENABLE_DELAY_US);
writePinHigh(HD44780_E_PIN);
wait_us(HD44780_ENABLE_DELAY_US);
// Read low nibble
for (int i = 0; i < 4; i++) {
data |= (readPin(data_pins[i]) << i);
}
writePinLow(HD44780_E_PIN);
return data;
}
bool hd44780_busy(void) {
return hd44780_read(false) & HD44780_BUSY_FLAG;
}
void hd44780_command(uint8_t command) {
while (hd44780_busy())
;
hd44780_write(command, false);
}
void hd44780_data(uint8_t data) {
while (hd44780_busy())
;
hd44780_write(data, true);
}
void hd44780_clear(void) {
hd44780_command(HD44780_CMD_CLEAR_DISPLAY);
}
void hd44780_home(void) {
hd44780_command(HD44780_CMD_RETURN_HOME);
}
void hd44780_on(bool cursor, bool blink) {
if (cursor) {
if (blink) {
hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON | HD44780_DISPLAY_CURSOR | HD44780_DISPLAY_BLINK);
} else {
hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON | HD44780_DISPLAY_CURSOR);
}
} else {
hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON);
}
}
void hd44780_off() {
hd44780_command(HD44780_CMD_DISPLAY);
}
void hd44780_set_cgram_address(uint8_t address) {
hd44780_command(HD44780_CMD_SET_CGRAM_ADDRESS + (address & 0x3F));
}
void hd44780_set_ddram_address(uint8_t address) {
hd44780_command(HD44780_CMD_SET_DDRAM_ADDRESS + (address & 0x7F));
}
void hd44780_init(bool cursor, bool blink) {
setPinOutput(HD44780_RS_PIN);
setPinOutput(HD44780_RW_PIN);
setPinOutput(HD44780_E_PIN);
for (int i = 0; i < 4; i++) {
setPinOutput(data_pins[i]);
}
wait_ms(HD44780_INIT_DELAY_MS);
// Manually configure for 4-bit mode - can't use hd44780_command() yet
// HD44780U datasheet, Fig. 24 (p46)
writePinHigh(data_pins[0]); // Function set
writePinHigh(data_pins[1]); // DL = 1
hd44780_latch();
wait_ms(5);
// Send again
hd44780_latch();
wait_us(64);
// And again (?)
hd44780_latch();
wait_us(64);
writePinLow(data_pins[0]); // DL = 0
hd44780_latch();
wait_us(64);
#if HD44780_DISPLAY_LINES == 1
hd44780_command(HD44780_CMD_FUNCTION); // 4 bit, 1 line, 5x8 dots
#else
hd44780_command(HD44780_CMD_FUNCTION | HD44780_FUNCTION_2_LINES); // 4 bit, 2 lines, 5x8 dots
#endif
hd44780_on(cursor, blink);
hd44780_clear();
hd44780_home();
hd44780_command(HD44780_CMD_ENTRY_MODE | HD44780_ENTRY_MODE_INC);
}
void hd44780_set_cursor(uint8_t col, uint8_t line) {
register uint8_t address = col;
#if HD44780_DISPLAY_LINES == 1
address += HD44780_DDRAM_LINE0_ADDR;
#elif HD44780_DISPLAY_LINES == 2
if (line == 0) {
address += HD44780_DDRAM_LINE0_ADDR;
} else {
address += HD44780_DDRAM_LINE1_ADDR;
}
#endif
hd44780_set_ddram_address(address);
}
void hd44780_define_char(uint8_t index, uint8_t *data) {
hd44780_set_cgram_address((index & 0x7) << 3);
for (uint8_t i = 0; i < 8; i++) {
hd44780_data(data[i]);
}
}
void hd44780_putc(char c) {
while (hd44780_busy())
;
uint8_t current_position = hd44780_read(false);
if (c == '\n') {
hd44780_set_cursor(0, current_position < HD44780_DDRAM_LINE1_ADDR ? 1 : 0);
} else {
#if defined(HD44780_WRAP_LINES)
# if HD44780_DISPLAY_LINES == 1
if (current_position == HD44780_DDRAM_LINE0_ADDR + HD44780_DISPLAY_COLS) {
// Go to start of line
hd44780_set_cursor(0, 0);
}
# elif HD44780_DISPLAY_LINES == 2
if (current_position == HD44780_DDRAM_LINE0_ADDR + HD44780_DISPLAY_COLS) {
// Go to start of second line
hd44780_set_cursor(0, 1);
} else if (current_position == HD44780_DDRAM_LINE1_ADDR + HD44780_DISPLAY_COLS) {
// Go to start of first line
hd44780_set_cursor(0, 0);
}
# endif
#endif
hd44780_data(c);
}
}
void hd44780_puts(const char *s) {
register char c;
while ((c = *s++)) {
hd44780_putc(c);
}
}
#if defined(__AVR__)
void hd44780_define_char_P(uint8_t index, const uint8_t *data) {
hd44780_set_cgram_address(index << 3);
for (uint8_t i = 0; i < 8; i++) {
hd44780_data(pgm_read_byte(data++));
}
}
void hd44780_puts_P(const char *s) {
register char c;
while ((c = pgm_read_byte(s++))) {
hd44780_putc(c);
}
}
#endif