driver: add hd44780 lcd support

drivers/hd44780/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

drivers/hd44780/hd44780.c

@@ -0,0 +1,295 @@
+/*
+ * 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++);
+    }
+}

drivers/hd44780/include/hd44780_internal.h

@@ -0,0 +1,100 @@
+/*
+ * 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 */