ARM Cortex-M3 (STM32F103) Tutorial - LCD 16x2 Library

In this tutorial, I will share about LCD 16x2 library. With this library, you can easily use LCD 16x2 with STM32F103 microcontroller. This library contain 2 file: lcd16x2.h and lcd16x2.c files. If you want to know the more detail how the LCD 16x2 works, you can see this tutorial.

In this library, we can configure GPIO for the LCD 16x2 on lcd16x2.h file. This definitions on lcd16x2.h contains GPIO configuration for LCD 16x2:

// LCD control lines (must be on the same port) 
#define LCD16X2_RCC_GPIO_CONTROL   RCC_APB2Periph_GPIOB
#define LCD16X2_GPIO_CONTROL       GPIOB
#define LCD16X2_GPIO_RS            GPIOB
#define LCD16X2_GPIO_RW            GPIOB
#define LCD16X2_GPIO_EN            GPIOB
// LCD data lines (must be on the same port)
#define LCD16X2_RCC_GPIO_DATA      RCC_APB2Periph_GPIOA
#define LCD16X2_GPIO_DATA          GPIOA
#define LCD16X2_GPIO_D4            GPIOA
#define LCD16X2_GPIO_D5            GPIOA
#define LCD16X2_GPIO_D6            GPIOA
#define LCD16X2_GPIO_D7            GPIOA
// Pin definition
#define LCD16X2_PIN_RS             GPIO_Pin_12
#define LCD16X2_PIN_RW             GPIO_Pin_13
#define LCD16X2_PIN_EN             GPIO_Pin_14
#define LCD16X2_PIN_D4             GPIO_Pin_8     // 4-bit mode LSB
#define LCD16X2_PIN_D5             GPIO_Pin_9
#define LCD16X2_PIN_D6             GPIO_Pin_10
#define LCD16X2_PIN_D7             GPIO_Pin_11    // 4-bit mode MSB

In this definitions, you can configure GPIO for LCD control lines (RS, RW, EN) and LCD data lines (D4-D7). This library only support 4-bit data mode.

To use this library, in the main.c file, you must call lcd16x2_init() function. There are 5 parameter for this function that can be used, depending on what type of cursor you want to use:

• LCD16X2_DISPLAY_OFF_CURSOR_OFF_BLINK_OFF
• LCD16X2_DISPLAY_ON_CURSOR_OFF_BLINK_OFF
• LCD16X2_DISPLAY_ON_CURSOR_OFF_BLINK_ON
• LCD16X2_DISPLAY_ON_CURSOR_ON_BLINK_OFF
• LCD16X2_DISPLAY_ON_CURSOR_ON_BLINK_ON

This library is also support custom character display. This code is an example for use the library for displaying a string and also custom character:

#include "stm32f10x.h"
#include "stm32f10x_rcc.h"
#include "stm32f10x_gpio.h"
#include "delay.h"
#include "lcd16x2.h"

// Custom char data (battery symbol)
uint8_t custom_char[] = { 0x0E, 0x1B, 0x11, 0x11, 0x11, 0x11, 0x1F, 0x1F };

int main(void)
{
    // Delay initialization
    DelayInit();

    // LCD initialization
    lcd16x2_init(LCD16X2_DISPLAY_ON_CURSOR_OFF_BLINK_OFF);

    // Create custom char
    lcd16x2_create_custom_char(0, custom_char);

    while (1)
    {
        // Display custom char
        lcd16x2_put_custom_char(0, 0, 0);
        lcd16x2_puts(" Battery Low");
        DelayMs(500);
        // Clear display
        lcd16x2_clrscr();
        DelayMs(500);
    }
}

The result will be like this:

You can download the library and example code from my repository.