Interfacing 16X2 LCD With STM32 & Cube IDE

Hello!

In this tutorial, you’ll learn how to interface STM32 with LCD 16×2 display and integrate the STM32 LCD library into your project. 

• STM32 Black pill board
• STM32 Cube IDE Software
• 16*2 LCD Display
• Jumper wires (M-M, F-M)
• USB –Type C cable
• Potentiometer- 10K
• Breadboard

• The first step is to make connections between the components.
• Make pin connection between LCD display and STM32 black pill board as shown in the images.
• Also use breadboard to connect potentiometer and resistor to LCD display and STM32 board.
• The project will work without making use of potentiometer and resistor but it is better to use potentiometer for display quality and resistor for durability.

• Open Cube IDE and go to Pinout and Configuration
• Now in Pinout view select the pins that you used in the hardware connections
• Here from the above step set PA1, PA3, PB0, PB1, PB10 and PB11 to GPIO_Output
• Now, to setup timer to create delay in microseconds, click on clock configuration >>HSE>>PLL CLK
• Now, select resolve clock issues from the top in the center
• Save the settings

• Add code in Inc folder that is inside Core
• The code is given below:

/*

 * lcd.h

 *

 * Created on: 10/06/2018

 *   Author: Olivier Van den Eede

 */

#ifndef LCD_H_

#define LCD_H_

#include "stm32f1xx_hal.h"

#include "string.h"

#include "stdio.h"

#include "main.h"

// #define LCD20xN // For 20xN LCDs

#define LCD16xN // For 16xN LCDs

// For row start addresses

extern const uint8_t ROW_16[];

extern const uint8_t ROW_20[];

/************************************* Command register **************************************/

#define CLEAR_DISPLAY 0x01

#define RETURN_HOME 0x02

#define ENTRY_MODE_SET 0x04

#define OPT_S 0x01 // Shift entire display to right

#define OPT_INC 0x02 // Cursor increment

#define DISPLAY_ON_OFF_CONTROL 0x08

#define OPT_D 0x04 // Turn on display

#define OPT_C 0x02 // Turn on cursor

#define OPT_B 0x01 // Turn on cursor blink

#define CURSOR_DISPLAY_SHIFT 0x10 // Move and shift cursor

#define OPT_SC 0x08

#define OPT_RL 0x04

#define FUNCTION_SET 0x20

#define OPT_DL 0x10 // Set interface data length

#define OPT_N 0x08 // Set number of display lines

#define OPT_F 0x04 // Set alternate font

#define SETCGRAM_ADDR 0x040

#define SET_DDRAM_ADDR 0x80 // Set DDRAM address

/************************************** Helper macros **************************************/

#define DELAY(X) HAL_Delay(X)

/************************************** LCD defines **************************************/

#define LCD_NIB 4

#define LCD_BYTE 8

#define LCD_DATA_REG 1

#define LCD_COMMAND_REG 0

/************************************** LCD typedefs **************************************/

#define Lcd_PortType GPIO_TypeDef*

#define Lcd_PinType uint16_t

typedef enum {

LCD_4_BIT_MODE,

LCD_8_BIT_MODE

} Lcd_ModeTypeDef;

typedef struct {

Lcd_PortType * data_port;

Lcd_PinType * data_pin;

Lcd_PortType rs_port;

Lcd_PinType rs_pin;

Lcd_PortType en_port;

Lcd_PinType en_pin;

Lcd_ModeTypeDef mode;}

Lcd_HandleTypeDef;

/************************************** Public functions **************************************/

void Lcd_init(Lcd_HandleTypeDef * lcd);

void Lcd_int(Lcd_HandleTypeDef * lcd, int number);

void Lcd_string(Lcd_HandleTypeDef * lcd, char * string);

void Lcd_cursor(Lcd_HandleTypeDef * lcd, uint8_t row, uint8_t col);

Lcd_HandleTypeDef Lcd_create(

Lcd_PortType port[], Lcd_PinType pin[],

Lcd_PortType rs_port, Lcd_PinType rs_pin,

Lcd_PortType en_port, Lcd_PinType en_pin, Lcd_ModeTypeDef mode);

void Lcd_define_char(Lcd_HandleTypeDef * lcd, uint8_t code, uint8_t bitmap[]);

void Lcd_clear(Lcd_HandleTypeDef * lcd);

#endif /* LCD_H_ */

/*

 * lcd.c

 *

 * Created on: 10/06/2018

 *   Author: Olivier Van den Eede

 */

#include "lcd.h"

const uint8_t ROW_16[] = {0x00, 0x40, 0x10, 0x50};

const uint8_t ROW_20[] = {0x00, 0x40, 0x14, 0x54};

/************************************** Static declarations **************************************/

static void lcd_write_data(Lcd_HandleTypeDef * lcd, uint8_t data);

static void lcd_write_command(Lcd_HandleTypeDef * lcd, uint8_t command);

static void lcd_write(Lcd_HandleTypeDef * lcd, uint8_t data, uint8_t len);

/************************************** Function definitions **************************************/

/**

 * Create new Lcd_HandleTypeDef and initialize the Lcd

 */

Lcd_HandleTypeDef Lcd_create(

Lcd_PortType port[], Lcd_PinType pin[],

Lcd_PortType rs_port, Lcd_PinType rs_pin,

Lcd_PortType en_port, Lcd_PinType en_pin, Lcd_ModeTypeDef mode)

{

Lcd_HandleTypeDef lcd;

lcd.mode = mode;

lcd.en_pin = en_pin;

lcd.en_port = en_port;

lcd.rs_pin = rs_pin;

lcd.rs_port = rs_port;

lcd.data_pin = pin;

lcd.data_port = port;

Lcd_init(&lcd);

return lcd;

}

/**

 * Initialize 16x2-lcd without cursor

 */

void Lcd_init(Lcd_HandleTypeDef * lcd)

{if(lcd->mode == LCD_4_BIT_MODE)

{lcd_write_command(lcd, 0x33);

lcd_write_command(lcd, 0x32);

lcd_write_command(lcd, FUNCTION_SET | OPT_N); // 4-bit mode

}

else

lcd_write_command(lcd, FUNCTION_SET | OPT_DL | OPT_N);

lcd_write_command(lcd, CLEAR_DISPLAY); // Clear screen

lcd_write_command(lcd, DISPLAY_ON_OFF_CONTROL | OPT_D); // Lcd-on, cursor-off, no-blink

lcd_write_command(lcd, ENTRY_MODE_SET | OPT_INC); // Increment cursor

}

/**

 * Write a number on the current position

 */

void Lcd_int(Lcd_HandleTypeDef * lcd, int number)

{

char buffer[11];

sprintf(buffer, "%d", number);

Lcd_string(lcd, buffer);

}

/**

 * Write a string on the current position

 */

void Lcd_string(Lcd_HandleTypeDef * lcd, char * string)

{

for(uint8_t i = 0; i < strlen(string); i++)

{lcd_write_data(lcd, string[i]);

}

}

/**

 * Set the cursor position

 */

void Lcd_cursor(Lcd_HandleTypeDef * lcd, uint8_t row, uint8_t col)

{

#ifdef LCD20xN

lcd_write_command(lcd, SET_DDRAM_ADDR + ROW_20[row] + col);

#endif

#ifdef LCD16xN

lcd_write_command(lcd, SET_DDRAM_ADDR + ROW_16[row] + col);

#endif

}

/**

 * Clear the screen

 */

void Lcd_clear(Lcd_HandleTypeDef * lcd) {

lcd_write_command(lcd, CLEAR_DISPLAY);

}

void Lcd_define_char(Lcd_HandleTypeDef * lcd, uint8_t code, uint8_t bitmap[]){

lcd_write_command(lcd, SETCGRAM_ADDR + (code << 3));

for(uint8_t i=0;i<8;++i){

lcd_write_data(lcd, bitmap[i]);

}

}

/************************************** Static function definition **************************************/

/**

 * Write a byte to the command register

 */

void lcd_write_command(Lcd_HandleTypeDef * lcd, uint8_t command)

{

HAL_GPIO_WritePin(lcd->rs_port, lcd->rs_pin, LCD_COMMAND_REG); // Write to command register

if(lcd->mode == LCD_4_BIT_MODE)

{lcd_write(lcd, (command >> 4), LCD_NIB);

lcd_write(lcd, command & 0x0F, LCD_NIB);}

else

{lcd_write(lcd, command, LCD_BYTE);}

}

/**

 * Write a byte to the data register

 */

void lcd_write_data(Lcd_HandleTypeDef * lcd, uint8_t data)

{

HAL_GPIO_WritePin(lcd->rs_port, lcd->rs_pin, LCD_DATA_REG); // Write to data register

if(lcd->mode == LCD_4_BIT_MODE)

{lcd_write(lcd, data >> 4, LCD_NIB);

lcd_write(lcd, data & 0x0F, LCD_NIB);}

else

{lcd_write(lcd, data, LCD_BYTE);}

}

/**

 * Set len bits on the bus and toggle the enable line

 */

void lcd_write(Lcd_HandleTypeDef * lcd, uint8_t data, uint8_t len

{

for(uint8_t i = 0; i < len; i++)

{HAL_GPIO_WritePin(lcd->data_port[i], lcd->data_pin[i], (data >> i) & 0x01);}

HAL_GPIO_WritePin(lcd->en_port, lcd->en_pin, 1);

DELAY(1);

HAL_GPIO_WritePin(lcd->en_port, lcd->en_pin, 0); // Data receive on falling edge

}

• Save and close the files

• Add #include "lcd.h" under /* USER CODE BEGIN Includes */
• Additional code on top of STM32CubeIDE generated code is given below:

// Lcd_PortType ports[] = { D4_GPIO_Port, D5_GPIO_Port, D6_GPIO_Port, D7_GPIO_Port };

Lcd_PortType ports[] = { GPIOB, GPIOB, GPIOB, GPIOB };

// Lcd_PinType pins[] = {D4_Pin, D5_Pin, D6_Pin, D7_Pin};

Lcd_PinType pins[] = {GPIO_PIN_0, GPIO_PIN_1, GPIO_PIN_10, GPIO_PIN_11};

Lcd_HandleTypeDef lcd;

// Lcd_create(ports, pins, RS_GPIO_Port, RS_Pin, EN_GPIO_Port, EN_Pin, LCD_4_BIT_MODE);

lcd = Lcd_create(ports, pins, GPIOA, GPIO_PIN_1, GPIOA, GPIO_PIN_3, LCD_4_BIT_MODE);

Lcd_cursor(&lcd, 0,1);

Lcd_string(&lcd, "Vanshika Rana");

for ( int x = 1; x <= 200 ; x++ )

{

Lcd_cursor(&lcd, 1,7);

Lcd_int(&lcd, x);

HAL_Delay (1000);}

• Now, copy path of project file generated
• Open STM32 cube programmer>>main.c (beside Device memory)>> Open file
• Enter file path and connect the STM32 black pill via USB cable
• Click on Download and fill the blank space with file path. Check the boxes and click on Start Automatic Mode
• The LCD displays your name