LiquidCrystal.c

#include "stm32f1xx_hal.h" // change this line accordingly
#include "LiquidCrystal.h"
#include <stdio.h>
#include <string.h>

// change this to 0 if you want to use 8-bit mode
uint8_t _fourbit_mode = 1;

// change this to LCD_5x10DOTS for some 1 line displays that can select a 10 pixel high font
uint8_t dotsize = LCD_5x8DOTS;

// pin definitions and other LCD variables
uint16_t _rs_pin; // LOW: command.  HIGH: character.
uint16_t _rw_pin; // LOW: write to LCD.  HIGH: read from LCD.
uint16_t _enable_pin; // activated by a HIGH pulse.
uint16_t _data_pins[8];
GPIO_TypeDef *_port;

uint8_t _displayfunction;
uint8_t _displaycontrol;
uint8_t _displaymode;

uint8_t _initialized;

uint8_t _numlines;
uint8_t _row_offsets[4];

void LiquidCrystal(GPIO_TypeDef *gpioport, uint16_t rs, uint16_t rw, uint16_t enable,
           uint16_t d0, uint16_t d1, uint16_t d2, uint16_t d3)
{
  if(_fourbit_mode)
    init(1, gpioport, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
  else
    init(0, gpioport, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}

void init(uint8_t fourbitmode, GPIO_TypeDef *gpioport, uint16_t rs, uint16_t rw, uint16_t enable,
       uint16_t d0, uint16_t d1, uint16_t d2, uint16_t d3,
       uint16_t d4, uint16_t d5, uint16_t d6, uint16_t d7)
{
  _rs_pin = rs;
  _rw_pin = rw;
  _enable_pin = enable;
  _port = gpioport;

  _data_pins[0] = d0;
  _data_pins[1] = d1;
  _data_pins[2] = d2;
  _data_pins[3] = d3;
  _data_pins[4] = d4;
  _data_pins[5] = d5;
  _data_pins[6] = d6;
  _data_pins[7] = d7;

  if (fourbitmode)
    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
  else
    _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;

 // begin(16, 2);
}

void begin(uint8_t cols, uint8_t lines) {
  if (lines > 1) {
    _displayfunction |= LCD_2LINE;
  }
  _numlines = lines;

  setRowOffsets(0x00, 0x40, 0x00 + cols, 0x40 + cols);

  // for some 1 line displays you can select a 10 pixel high font
  if ((dotsize != LCD_5x8DOTS) && (lines == 1)) {
    _displayfunction |= LCD_5x10DOTS;
  }

  //Initializing GPIO Pins
  enableClock();

  GPIO_InitTypeDef gpio_init;
  gpio_init.Speed = GPIO_SPEED_FREQ_HIGH;
  gpio_init.Mode = GPIO_MODE_OUTPUT_PP;

 if(_fourbit_mode)
    gpio_init.Pin = _rs_pin | _rw_pin | _enable_pin | _data_pins[0] | _data_pins[1] | _data_pins[2] | _data_pins[3];
  else
    gpio_init.Pin = _rs_pin | _rw_pin | _enable_pin | _data_pins[0] | _data_pins[1] | _data_pins[2] | _data_pins[3] |
                    _data_pins[4] | _data_pins[5] | _data_pins[6] | _data_pins[7];
// SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
// according to datasheet, we need at least 40ms after power rises above 2.7V
// so we'll wait 50 just to make sure
  HAL_Delay(50);

  // Now we pull both RS and R/W low to begin commands
  HAL_GPIO_WritePin(_port, _rs_pin, GPIO_PIN_RESET);
  HAL_GPIO_WritePin(_port, _enable_pin, GPIO_PIN_RESET);

  if (_rw_pin != 255) {
    HAL_GPIO_WritePin(_port, _rw_pin, GPIO_PIN_RESET);
  }

  //put the LCD into 4 bit or 8 bit mode
  if (! (_displayfunction & LCD_8BITMODE)) {
    // this is according to the hitachi HD44780 datasheet
    // figure 24, pg 46

    // we start in 8bit mode, try to set 4 bit mode
    write4bits(0x03);
    HAL_Delay(5); // wait min 4.1ms

    // second try
    write4bits(0x03);
    HAL_Delay(5); // wait min 4.1ms

    // third go!
    write4bits(0x03);
    HAL_Delay(1);

    // finally, set to 4-bit interface
    write4bits(0x02);
  } else {
    // this is according to the hitachi HD44780 datasheet
    // page 45 figure 23

    // Send function set command sequence
    command(LCD_FUNCTIONSET | _displayfunction);
    HAL_Delay(5);  // wait more than 4.1ms

    // second try
    command(LCD_FUNCTIONSET | _displayfunction);
    HAL_Delay(1);

    // third go
    command(LCD_FUNCTIONSET | _displayfunction);
  }

  // finally, set # lines, font size, etc.
  command(LCD_FUNCTIONSET | _displayfunction);

  // turn the display on with no cursor or blinking default
  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
  display();

  // clear it off
  clear();

  // Initialize to default text direction (for romance languages)
  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
  // set the entry mode
  command(LCD_ENTRYMODESET | _displaymode);

}

// enables GPIO RCC Clock
void enableClock(void)
{
  if(_port == GPIOA)
    __HAL_RCC_GPIOA_CLK_ENABLE();
  else if(_port == GPIOB)
    __HAL_RCC_GPIOB_CLK_ENABLE();
  else if(_port == GPIOB)
    __HAL_RCC_GPIOB_CLK_ENABLE();
  else if(_port == GPIOC)
    __HAL_RCC_GPIOC_CLK_ENABLE();
  else if(_port == GPIOD)
    __HAL_RCC_GPIOD_CLK_ENABLE();

  // if you have a port that is not listed add it below the other else ifs
}

void setRowOffsets(int row0, int row1, int row2, int row3)
{
  _row_offsets[0] = row0;
  _row_offsets[1] = row1;
  _row_offsets[2] = row2;
  _row_offsets[3] = row3;
}

/********** high level commands, for the user! */
void clear(void)
{
  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
  HAL_Delay(2);  // this command takes a long time!
}

void home(void)
{
  command(LCD_RETURNHOME);  // set cursor position to zero
  HAL_Delay(2);  // this command takes a long time!
}

void setCursor(uint8_t col, uint8_t row)
{
  const size_t max_lines = sizeof(_row_offsets) / sizeof(*_row_offsets);
  if ( row >= max_lines ) {
    row = max_lines - 1;    // we count rows starting w/0
  }
  if ( row >= _numlines ) {
    row = _numlines - 1;    // we count rows starting w/0
  }

  command(LCD_SETDDRAMADDR | (col + _row_offsets[row]));
}

// Turn the display on/off (quickly)
void noDisplay(void) {
  _displaycontrol &= ~LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void display(void) {
  _displaycontrol |= LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turns the underline cursor on/off
void noCursor(void) {
  _displaycontrol &= ~LCD_CURSORON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void cursor(void) {
  _displaycontrol |= LCD_CURSORON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turn on and off the blinking cursor
void noBlink(void) {
  _displaycontrol &= ~LCD_BLINKON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void blink(void) {
  _displaycontrol |= LCD_BLINKON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// These commands scroll the display without changing the RAM
void scrollDisplayLeft(void) {
  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}
void scrollDisplayRight(void) {
  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}

// This is for text that flows Left to Right
void leftToRight(void) {
  _displaymode |= LCD_ENTRYLEFT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// This is for text that flows Right to Left
void rightToLeft(void) {
  _displaymode &= ~LCD_ENTRYLEFT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'right justify' text from the cursor
void autoscroll(void) {
  _displaymode |= LCD_ENTRYSHIFTINCREMENT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'left justify' text from the cursor
void noAutoscroll(void) {
  _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// This will print character string to the LCD
size_t print(const char str[]) {
  if (str == NULL) return 0;

  const uint8_t *buffer = (const uint8_t *)str;
  size_t size = strlen(str);
  size_t n = 0;

  while (size--) {
    if (write(*buffer++)) n++;
    else break;
  }
  return n;
}

// Allows us to fill the first 8 CGRAM locations
// with custom characters
void createChar(uint8_t location, uint8_t charmap[]) {
  location &= 0x7; // we only have 8 locations 0-7
  command(LCD_SETCGRAMADDR | (location << 3));
  for (int i=0; i<8; i++) {
    write(charmap[i]);
  }
}

/*********** mid level commands, for sending data/cmds */

inline void command(uint8_t value) {
  send(value, GPIO_PIN_RESET);
}

inline size_t write(uint8_t value) {
  send(value, GPIO_PIN_SET);
  return 1; // assume sucess
}

/************ low level data pushing commands **********/

// write either command or data, with automatic 4/8-bit selection
void send(uint8_t value, GPIO_PinState mode) {
  HAL_GPIO_WritePin(_port, _rs_pin, mode);

  // if there is a RW pin indicated, set it low to Write
  if (_rw_pin != 255) {
    HAL_GPIO_WritePin(_port, _rw_pin, GPIO_PIN_RESET);
  }

  if (_displayfunction & LCD_8BITMODE) {
    write8bits(value);
  } else {
    write4bits(value>>4);
    write4bits(value);
  }
}

void pulseEnable(void) {
  HAL_GPIO_WritePin(_port, _enable_pin, GPIO_PIN_RESET);
  HAL_Delay(1);
  HAL_GPIO_WritePin(_port, _enable_pin, GPIO_PIN_SET);
  HAL_Delay(1);    // enable pulse must be >450ns
  HAL_GPIO_WritePin(_port, _enable_pin, GPIO_PIN_RESET);
  HAL_Delay(1);   // commands need > 37us to settle
}

void write4bits(uint8_t value) {
  for (int i = 0; i < 4; i++) {
    HAL_GPIO_WritePin(_port, _data_pins[i], ((value >> i) & 0x01)?GPIO_PIN_SET:GPIO_PIN_RESET);
  }

  pulseEnable();
}

void write8bits(uint8_t value) {
  for (int i = 0; i < 8; i++) {
    HAL_GPIO_WritePin(_port, _data_pins[i], ((value >> i) & 0x01)?GPIO_PIN_SET:GPIO_PIN_RESET);
  }

  pulseEnable();
}