Created for Ouroboros Embedded Education.

Versions Changelog

V1.0.0

• Initial Release

Introduction

This is a simple library to work with the LCD Alphanumeric Display, encountered in many sizes and colors.

An applicable LCD Display can be seen below:

This lib aiming to provide this advantages:

• Allow use any amount of displays you want;
• Easy port to any chipsets, without any direct link with the microcontroller;
• Easy to configure;
• For noobies and professionais.

Files

lcdDisplay.c / lcdDisplay.h

Contains the Lcd logic functions and the Lcd Handler.

Platform Folder

In this folder we have the platform.h file with contains the chipset functions must be implemented by the user.

The platform_blank.c contains only the template to start the writing. I recommend you to copy this file and paste on your application folder. Please, do not forget to remove this file from your build configuration.

Structure

The lcd_t handler will be explained below:

typedef struct{
	/* The array containing the GPIO and Pins where the Lcd is connected */
	gpio_t gpios[LCD_PIN_QTD];
	/* How amount Columns you Lcd have, if you display is a 
	 * 20x4, so, your columns will be 20
	 */
	uint32_t columns;
	/* How amount Rows you Lcd have, if you display is a 
	 * 20x4, so, your rows will be 4
	 */
	uint32_t rows;
	/* The program must know how you wired the Data pins of your LCD.
	 * LCD_INTERFACE_4BIT: if you connected D4~D7 pins
	 * LCD_INTERFACE_8BIT: if you connected D0~D7 pins
	 */
	lcd_interface_mode_e interface;
	/* Tell the font sizing of the display.
	 * LCD_FONT_5X8: Most common
	 * LCD_FONT_5X10: A bigger version of the lcd display.
	 */
	lcd_font_type_e font;
	//backlight control, pick one, or no one
	/* Only Set one of this parameters if you have the backlight control */
	/* If you controlling a On/Off of the LCD, inform the GPIO and Pin
	 * For the moment, the HIGH level is to turn on the LCD (NPN Transistor)
	 */
	gpio_t backlightGpio;
	/* Provide the Timer Peripheral Handler and the Channel of
	 * the PWM channel to set the Lcd brightness level over the lib.
	 * 100% indicates full brightness, and 0% will turnoff.
	 */
	pwm_t backlightPwm;
	// !! please, do not customize this values !!
	uint8_t _cursor;
	uint8_t _column;
	uint8_t _row;
}lcd_t;

And, to the handler knows what GPIOs to drive, the gpio_t is the type of the gpios parameter on the lcd_t handler. So, the developer must inform all connected GPIOs.

typedef struct{
	/* The GPIO handler of your MCU, some uc do not have
	 * the GPIO handler, only the Pin (nRF52810, CC26x2R1, for example)
	 */
	uint32_t GPIO;
	/* The Pin number parameter. Some MCUs has only this parameters
	 * to identify your GPIOs*/
	uint32_t pin;
	/* Example of providing this parameters:
	 * ::for STM32::
	 * gpios.GPIO = (uint32_t)GPIOA
	 * gpios.pin = GPIO_PIN3
	 */
}gpio_t;

Note: I will talk about PWM later.

Functions

/**
 * @brief Initialize the display.
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_init (lcd_t *lcd);  

/**
 * @brief Disables the cursor blink.
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_blink_off(lcd_t *lcd);

/**
 * @brief Enables the cursor blink
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_blink_on(lcd_t *lcd);

/**
 * @brief Disables the underline cursor
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_cursor_off(lcd_t *lcd);

/**
 * @brief Enables the underline cursor
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_cursor_on(lcd_t *lcd);

/**
 * @brief Turnoff the display without losing data
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_display_off(lcd_t *lcd);

/**
 * @brief Turn on back the display
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_display_on(lcd_t *lcd);

/**
 * @brief Sends a Command to the display;
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param cmd : Command to issue to the Lcd, see lcd_cmd_e enum.
 */
void lcd_cmd (lcd_t *lcd, lcd_cmd_e cmd);  // send command to the lcd

/**
 * @brief Issue a raw byte data to the Lcd
 * 
 * @param lcd  : pointer to the Lcd Handler
 * @param data : the data byte
 */
void lcd_data (lcd_t *lcd, uint8_t data);

/**
 * @brief Change the cursor position on the Lcd pannel.
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param row : desired row. The command will not be sent if row is greater than lcd->rows.
 * @param col : desired column. The command will not be sent if row is greater than lcd->columns.
 */
void lcd_put_pos(lcd_t *lcd, uint8_t row, uint8_t col);  

/**
 * @brief Send a char on the actual cursor position. Char can be a custom char, see the lcd_custom_char_e.
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param data : the desired char
 */
void lcd_send_char (lcd_t *lcd, char data);  

/**
 * @brief Send a string, that starts on the actual cursor position. The library will 
 * automatically stops when reach the end of the display.
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param str : array of characters containing the string
 */
void lcd_send_string (lcd_t *lcd, char *str);  // send string to the lcd

/**
 * @brief Send a char on the desired position
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param data : the desired char
 * @param row : desired row. The command will not be sent if row is greater than lcd->rows.
 * @param col : desired column. The command will not be sent if row is greater than lcd->columns.
 */
void lcd_send_char_pos(lcd_t *lcd, char data, uint8_t row, uint8_t col);

/**
 * @brief Send a string, that starts on the provided row and column. The library will 
 * automatically stops when reach the end of the display.
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param str : array of characters containing the string
 * @param row : desired row. The command will not be sent if row is greater than lcd->rows.
 * @param col : desired column. The command will not be sent if row is greater than lcd->columns.
 */
void lcd_send_string_pos (lcd_t *lcd, char *str, uint8_t row, uint8_t col);

/**
 * @brief Fills with blank only the desired row.
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param row : the row to be cleared.
 */
void lcd_clear_row (lcd_t *lcd, uint8_t row);

/**
 * @brief Clears the entire display
 * 
 * @param lcd : pointer to the Lcd Handler
 */
void lcd_clear_all (lcd_t *lcd);

/**
 * @brief Creates a custom character
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param custom : The custom position starting from LCD_CUSTOM_1 to LCD_CUSTOM_8
 * @param bitmap : The bitmap array
 */
void lcd_create_custom_char (lcd_t *lcd, lcd_custom_char_e custom, uint8_t *bitmap);

/**
 * @brief Sets the display backlight to on or off.
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param state : LCD_BACKLIGHT_ON to turnon display or LCD_BACKLIGHT_OFF to turnoff (really?)
 */
void lcd_backlight_set (lcd_t *lcd, uint8_t state);

/**
 * @brief Sets the display brightness based on a percentage. To use this, the developer
 * must implements an PWM.
 * 
 * @param lcd : pointer to the Lcd Handler
 * @param level : You can set this value from 0 to 100, where 0 is the minumum brightness, and
 * 100, the maximum.
 */
void lcd_backlight_set_bright (lcd_t *lcd, uint8_t level);

Quick Start Steps

See the example.

Examples

We have one provided for the moment.