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driver: add hd44780 lcd support

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pr/rotary
smlng 6 years ago
parent e9e9656e35
commit 26ec9041a0
4 changed files with 614 additions and 0 deletions
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1
drivers/hd44780/Makefile
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include $(RIOTBASE)/Makefile.base

295
drivers/hd44780/hd44780.c
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/*
* Copyright (C) 2017 HAW Hamburg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup drivers_hd44780
*
* @{
* @file
* @brief Driver for the HD44780 LCD
*
* @note The display is also known as LCM1602C from Arduino kits
*
* @author Sebastian Meiling <s@mlng.net>
*/
#include <assert.h>
#include <string.h>
#include "log.h"
#include "periph/gpio.h"
#include "xtimer.h"
#include "hd44780.h"
#include "hd44780_internal.h"
static inline void _command(hd44780_t *dev, uint8_t value);
static void _pulse(hd44780_t *dev);
static void _send(hd44780_t *dev, uint8_t value, uint8_t mode);
static void _write_bits(hd44780_t *dev, uint8_t bits, uint8_t value);
/**
* @brief Send a command to the display
*
* @param[in] dev device descriptor of display to initialize
* @param[in] value the command
*/
static inline void _command(hd44780_t *dev, uint8_t value)
{
_send(dev, value, HD44780_OFF);
}
/**
* @brief Send a pulse to the display to enable new state
*
* @param[in] dev device descriptor of display to initialize
*/
static void _pulse(hd44780_t *dev)
{
gpio_clear(dev->p.enable);
xtimer_usleep(HD44780_PULSE_WAIT_SHORT);
gpio_set(dev->p.enable);
xtimer_usleep(HD44780_PULSE_WAIT_SHORT);
gpio_clear(dev->p.enable);
xtimer_usleep(HD44780_PULSE_WAIT_LONG);
}
/**
* @brief Send a data value to the display
*
* @param[in] dev device descriptor of display to initialize
* @param[in] value the data value, either char or command
* @param[in] state send state, to distinguish chars and commands
*/
static void _send(hd44780_t *dev, uint8_t value, hd44780_state_t state)
{
(state == HD44780_ON) ? gpio_set(dev->p.rs) : gpio_clear(dev->p.rs);
/* if RW pin is available, set it to LOW */
if (dev->p.rw != HD44780_RW_OFF) {
gpio_clear(dev->p.rw);
}
/* write data in 8Bit or 4Bit mode */
if (dev->flag & HD44780_8BITMODE) {
_write_bits(dev, 8, value);
}
else {
_write_bits(dev, 4, value>>4);
_write_bits(dev, 4, value);
}
}
static void _write_bits(hd44780_t *dev, uint8_t bits, uint8_t value)
{
for (unsigned i = 0; i < bits; ++i) {
if ((value >> i) & 0x01) {
gpio_set(dev->p.data[i]);
}
else {
gpio_clear(dev->p.data[i]);
}
}
_pulse(dev);
}
int hd44780_init(hd44780_t *dev, const hd44780_params_t *params)
{
/* write config params to device descriptor */
memcpy(&dev->p, params, sizeof(hd44780_params_t));
/* verify cols and rows */
if ((dev->p.cols > HD44780_MAX_COLS) || (dev->p.rows > HD44780_MAX_ROWS)
|| (dev->p.rows * dev->p.cols > 80)) {
LOG_ERROR("hd44780_init: invalid LCD size!\n");
return -1;
}
uint8_t count_pins = 0;
/* check which pins are used */
for (unsigned i = 0; i < HD44780_MAX_PINS; ++i) {
if (dev->p.data[i] != HD44780_RW_OFF) {
++count_pins;
}
}
/* set mode depending on configured pins */
if (count_pins < HD44780_MAX_PINS) {
dev->flag |= HD44780_4BITMODE;
}
else {
dev->flag |= HD44780_8BITMODE;
}
/* set flag for 1 or 2 row mode, 4 rows are 2 rows split half */
if (dev->p.rows > 1) {
dev->flag |= HD44780_2LINE;
}
else {
dev->flag |= HD44780_1LINE;
}
/* set char size to 5x8 as default, 5x10 is hardly used by LCDs anyway */
dev->flag |= HD44780_5x8DOTS;
/* calc and set row offsets, depending on number of columns */
dev->roff[0] = 0x00;
dev->roff[1] = 0x40;
dev->roff[2] = 0x00 + dev->p.cols;
dev->roff[3] = 0x40 + dev->p.cols;
gpio_init(dev->p.rs, GPIO_OUT);
/* RW (read/write) of LCD not required, set it to HD44780_RW_OFF (255) */
if (dev->p.rw != HD44780_RW_OFF) {
gpio_init(dev->p.rw, GPIO_OUT);
}
gpio_init(dev->p.enable, GPIO_OUT);
/* configure all data pins as output */
for (int i = 0; i < ((dev->flag & HD44780_8BITMODE) ? 8 : 4); ++i) {
gpio_init(dev->p.data[i], GPIO_OUT);
}
/* see hitachi HD44780 datasheet pages 45/46 for init specs */
xtimer_usleep(HD44780_INIT_WAIT_XXL);
gpio_clear(dev->p.rs);
gpio_clear(dev->p.enable);
if (dev->p.rw != HD44780_RW_OFF) {
gpio_clear(dev->p.rw);
}
/* put the LCD into 4 bit or 8 bit mode */
if (!(dev->flag & HD44780_8BITMODE)) {
/* see hitachi HD44780 datasheet figure 24, pg 46 */
_write_bits(dev, 4, 0x03);
xtimer_usleep(HD44780_INIT_WAIT_LONG);
_write_bits(dev, 4, 0x03);
xtimer_usleep(HD44780_INIT_WAIT_LONG);
_write_bits(dev, 4, 0x03);
xtimer_usleep(HD44780_INIT_WAIT_SHORT);
_write_bits(dev, 4, 0x02);
} else {
/* see hitachi HD44780 datasheet page 45 figure 23 */
_command(dev, HD44780_FUNCTIONSET | dev->flag);
xtimer_usleep(HD44780_INIT_WAIT_LONG); // wait more than 4.1ms
_command(dev, HD44780_FUNCTIONSET | dev->flag);
xtimer_usleep(HD44780_INIT_WAIT_SHORT);
_command(dev, HD44780_FUNCTIONSET | dev->flag);
}
_command(dev, HD44780_FUNCTIONSET | dev->flag);
/* turn the display on with no cursor or blinking default, and clear */
dev->ctrl = HD44780_DISPLAYON | HD44780_CURSOROFF | HD44780_BLINKOFF;
hd44780_display(dev, HD44780_ON);
hd44780_clear(dev);
/* Initialize to default text direction for western languages */
dev->mode = HD44780_ENTRYLEFT | HD44780_ENTRYSHIFTDECREMENT;
_command(dev, HD44780_ENTRYMODESET | dev->mode);
return 0;
}
void hd44780_clear(hd44780_t *dev)
{
_command(dev, HD44780_CLEARDISPLAY);
xtimer_usleep(HD44780_CMD_WAIT);
}
void hd44780_home(hd44780_t *dev)
{
_command(dev, HD44780_RETURNHOME);
xtimer_usleep(HD44780_CMD_WAIT);
}
void hd44780_set_cursor(hd44780_t *dev, uint8_t col, uint8_t row)
{
if (row >= dev->p.rows) {
row = dev->p.rows - 1;
}
_command(dev, HD44780_SETDDRAMADDR | (col + dev->roff[row]));
}
void hd44780_display(hd44780_t *dev, hd44780_state_t state)
{
if (state == HD44780_ON) {
dev->ctrl |= HD44780_DISPLAYON;
}
else {
dev->ctrl &= ~HD44780_DISPLAYON;
}
_command(dev, HD44780_DISPLAYCONTROL | dev->ctrl);
}
void hd44780_cursor(hd44780_t *dev, hd44780_state_t state)
{
if (state == HD44780_ON) {
dev->ctrl |= HD44780_CURSORON;
}
else {
dev->ctrl &= ~HD44780_CURSORON;
}
_command(dev, HD44780_DISPLAYCONTROL | dev->ctrl);
}
void hd44780_blink(hd44780_t *dev, hd44780_state_t state)
{
if (state == HD44780_ON) {
dev->ctrl |= HD44780_BLINKON;
}
else {
dev->ctrl &= ~HD44780_BLINKON;
}
_command(dev, HD44780_DISPLAYCONTROL | dev->ctrl);
}
void hd44780_scroll_left(hd44780_t *dev)
{
_command(dev, HD44780_CURSORSHIFT | HD44780_DISPLAYMOVE | HD44780_MOVELEFT);
}
void hd44780_scroll_right(hd44780_t *dev) {
_command(dev, HD44780_CURSORSHIFT | HD44780_DISPLAYMOVE | HD44780_MOVERIGHT);
}
void hd44780_left2right(hd44780_t *dev)
{
dev->mode |= HD44780_ENTRYLEFT;
_command(dev, HD44780_ENTRYMODESET | dev->mode);
}
void hd44780_right2left(hd44780_t *dev)
{
dev->mode &= ~HD44780_ENTRYLEFT;
_command(dev, HD44780_ENTRYMODESET | dev->mode);
}
void hd44780_autoscroll(hd44780_t *dev, hd44780_state_t state)
{
if (state == HD44780_ON) {
dev->mode |= HD44780_ENTRYSHIFTINCREMENT;
}
else {
dev->mode &= ~HD44780_ENTRYSHIFTINCREMENT;
}
_command(dev, HD44780_ENTRYMODESET | dev->mode);
}
void hd44780_create_char(hd44780_t *dev, uint8_t location, uint8_t charmap[])
{
location &= 0x7; /* 8 locations (0-7) possible */
_command(dev, HD44780_SETCGRAMADDR | (location << 3));
for (unsigned i = 0; i < HD44780_CGRAM_SIZE; ++i) {
hd44780_write(dev, charmap[i]);
}
}
void hd44780_write(hd44780_t *dev, uint8_t value)
{
_send(dev, value, HD44780_ON);
}
void hd44780_print(hd44780_t *dev, const char *data )
{
while (*data != '\0') {
hd44780_write(dev, *data++);
}
}

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drivers/hd44780/include/hd44780_internal.h
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/*
* Copyright (C) 2017 HAW Hamburg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup drivers_hd44780
*
* @{
* @file
* @brief Internal config and parameters for the HD44780 display
*
* @author Sebastian Meiling <s@mlng.net>
*/
#ifndef HD44780_INTERNAL_H
#define HD44780_INTERNAL_H
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief HD44780 LCD commands
* @{
*/
#define HD44780_CLEARDISPLAY (0x01)
#define HD44780_RETURNHOME (0x02)
#define HD44780_ENTRYMODESET (0x04)
#define HD44780_DISPLAYCONTROL (0x08)
#define HD44780_CURSORSHIFT (0x10)
#define HD44780_FUNCTIONSET (0x20)
#define HD44780_SETCGRAMADDR (0x40)
#define HD44780_SETDDRAMADDR (0x80)
/**@}*/
/**
* @brief HD44780 LCD entry modes flags
* @{
*/
#define HD44780_ENTRYRIGHT (0x00)
#define HD44780_ENTRYLEFT (0x02)
#define HD44780_ENTRYSHIFTINCREMENT (0x01)
#define HD44780_ENTRYSHIFTDECREMENT (0x00)
/**@}*/
/**
* @brief HD44780 LCD control flags
* @{
*/
#define HD44780_DISPLAYON (0x04)
#define HD44780_DISPLAYOFF (0x00)
#define HD44780_CURSORON (0x02)
#define HD44780_CURSOROFF (0x00)
#define HD44780_BLINKON (0x01)
#define HD44780_BLINKOFF (0x00)
/**@}*/
/**
* @brief HD44780 display and cursor shift flags
* @{
*/
#define HD44780_DISPLAYMOVE (0x08)
#define HD44780_CURSORMOVE (0x00)
#define HD44780_MOVERIGHT (0x04)
#define HD44780_MOVELEFT (0x00)
/**@}*/
/**
* @brief HD44780 LCD functional flags
* @{
*/
#define HD44780_8BITMODE (0x10)
#define HD44780_4BITMODE (0x00)
#define HD44780_2LINE (0x08)
#define HD44780_1LINE (0x00)
#define HD44780_5x10DOTS (0x04)
#define HD44780_5x8DOTS (0x00)
/**@}*/
/**
* @brief HD44780 LCD timings
* @{
*/
#define HD44780_CMD_WAIT (2000U)
#define HD44780_INIT_WAIT_XXL (50000U)
#define HD44780_INIT_WAIT_LONG (4500U)
#define HD44780_INIT_WAIT_SHORT (150U)
#define HD44780_PULSE_WAIT_SHORT (1U)
#define HD44780_PULSE_WAIT_LONG (100U)
/**@}*/
#ifdef __cplusplus
}
#endif
#endif /* HD44780_INTERNAL_H */

218
drivers/include/hd44780.h
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/*
* Copyright (C) 2017 HAW Hamburg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup drivers_hd44780 HD44780 LCD driver
* @ingroup drivers_displays
* @brief Driver for the Hitachi HD44780 LCD driver
*
* @note The driver currently supports direct addressing, no I2C
*
* @{
*
* @file
* @brief Interface definition for the HD44780 LCD driver
*
* @author Sebastian Meiling <s@mlng.net>
*/
#ifndef HD44780_H
#define HD44780_H
#include <stdint.h>
#include "periph/gpio.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Maximal number of columns supported by the driver
*/
#define HD44780_MAX_COLS (40U)
/**
* @brief Maximal number of rows supported by the driver
*/
#define HD44780_MAX_ROWS (4U)
/**
* @brief Number of data pins for communication 4 or 8.
*/
#define HD44780_MAX_PINS (8U)
/**
* @brief Specific value to turn rw pin off, if unused.
*/
#define HD44780_RW_OFF (255U)
/**
* @brief Size of RAM for custom chars
*
* Generally the driver could support 8 chars of size 5x8 or 4 of size 5x10.
* However, most displays only use the former, which is (hard wired) default.
*/
#define HD44780_CGRAM_SIZE (8U)
/**
* @brief Parameters needed for device initialization
*/
typedef struct {
uint8_t cols; /**< number of LCD cols */
uint8_t rows; /**< number of LCD rows */
gpio_t rs; /**< rs gpio pin */
gpio_t rw; /**< rw gpio pin */
gpio_t enable; /**< enable gpio pin */
gpio_t data[8]; /**< data gpio pins */
} hd44780_params_t;
/**
* @brief Device descriptor for HD44780 LCD
*/
typedef struct {
hd44780_params_t p; /**< LCD config parameters */
uint8_t flag; /**< LCD functional flags */
uint8_t ctrl; /**< LCD control flags */
uint8_t mode; /**< LCD mode flags */
uint8_t roff[HD44780_MAX_ROWS]; /**< offsets for LCD rows */
} hd44780_t;
/**
* @brief Simple state values
*/
typedef enum {
HD44780_OFF, /**< disable feature */
HD44780_ON /**< enable feature */
} hd44780_state_t;
/**
* @brief Initialize the given driver
*
* @param[out] dev device descriptor of display to initialize
* @param[in] params configuration parameters
*
* @return 0 on success, otherwise error
*/
int hd44780_init(hd44780_t *dev, const hd44780_params_t *params);
/**
* @brief Clear display, delete all chars
*
* @param[in] dev device descriptor of LCD
*/
void hd44780_clear(hd44780_t *dev);
/**
* @brief Reset cursor to row 0 and column 0
*
* @param[in] dev device descriptor of LCD
*/
void hd44780_home(hd44780_t *dev);
/**
* @brief Set cursor to specific position in column and row
*
* @param[in] dev device descriptor of LCD
* @param[in] col column position
* @param[in] row row position
*/
void hd44780_set_cursor(hd44780_t *dev, uint8_t col, uint8_t row);
/**
* @brief Turn display on or off
*
* @param[in] dev device descriptor of LCD
* @param[in] state display on or off
*/
void hd44780_display(hd44780_t *dev, hd44780_state_t state);
/**
* @brief Show cursor, on or off
*
* @param[in] dev device descriptor of LCD
* @param[in] state cursor on or off
*/
void hd44780_cursor(hd44780_t *dev, hd44780_state_t state);
/**
* @brief Blink cursor, on or off
*
* @param[in] dev device descriptor of LCD
* @param[in] state blink on or off
*/
void hd44780_blink(hd44780_t *dev, hd44780_state_t state);
/**
* @brief Enable left scrolling
*
* @param[in] dev device descriptor of LCD
*/
void hd44780_scroll_left(hd44780_t *dev);
/**
* @brief Enable right scrolling
*
* @param[in] dev device descriptor of LCD
*/
void hd44780_scroll_right(hd44780_t *dev);
/**
* @brief set display direction left to right
*
* @param[in] dev device descriptor of LCD
*/
void hd44780_left2right(hd44780_t *dev);
/**
* @brief set display direction right to left
*
* @param[in] dev device descriptor of LCD
*/
void hd44780_right2left(hd44780_t *dev);
/**
* @brief display autoscroll on or off
*
* @param[in] dev device descriptor of LCD
* @param[in] state scroll on or off
*/
void hd44780_autoscroll(hd44780_t *dev, hd44780_state_t state);
/**
* @brief Create and store a custom character on display memory
*
* @param[in] dev device descriptor of LCD
* @param[in] location memory location
* @param[in] charmap character bitmap
*
* @pre charmap has to be of size HD44780_CGRAM_SIZE, which is 8 by default
*/
void hd44780_create_char(hd44780_t *dev, uint8_t location, uint8_t charmap[]);
/**
* @brief Write a single character on the LCD
*
* @param[in] dev device descriptor of LCD
* @param[in] value the character to print, i.e., memory location
*/
void hd44780_write(hd44780_t *dev, uint8_t value);
/**
* @brief Write a string on the LCD
*
* @param[in] dev device descriptor of LCD
* @param[in] data the string to print
*/
void hd44780_print(hd44780_t *dev, const char *data);
#ifdef __cplusplus
}
#endif
#endif /* HD44780_H */
/** @} */
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