Display string on NUCLEO-U575ZI-Q by 16x2 LCD with I2c driver

SMusc.1 · ‎2025-04-14

Good morning, I have been trying to make simple characters appear on the 16x2 character LCD display for a while now and I am using a U575ZI-Q core board. I have followed many tutorials but none of them have allowed me to display a simple line of text on the display.
I would like to point out that with the Arduino board I have no difficulty displaying simple characters like hello word, but with this board I can't. I am using two libraries in a row and the following code in the main.c file. Could you help me? The 16x2 LCD display has the I2C driver with a PCF8574T integrated circuit.


/* USER CODE BEGIN Header */

/**

******************************************************************************

* @file : main.c

* @brief : Main program body

******************************************************************************

* @attention

*

* Copyright (c) 2025 STMicroelectronics.

* All rights reserved.

*

* This software is licensed under terms that can be found in the LICENSE file

* in the root directory of this software component.

* If no LICENSE file comes with this software, it is provided AS-IS.

*

******************************************************************************

*/

/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/

#include "main.h"

#include "i2c.h"

#include "memorymap.h"

#include "gpio.h"



/* Private includes ----------------------------------------------------------*/

/* USER CODE BEGIN Includes */

#include "i2c_lcd.h"

/* USER CODE END Includes */



/* Private typedef -----------------------------------------------------------*/

/* USER CODE BEGIN PTD */



/* USER CODE END PTD */



/* Private define ------------------------------------------------------------*/

/* USER CODE BEGIN PD */



/* USER CODE END PD */



/* Private macro -------------------------------------------------------------*/

/* USER CODE BEGIN PM */



/* USER CODE END PM */



/* Private variables ---------------------------------------------------------*/



/* USER CODE BEGIN PV */



/* USER CODE END PV */



/* Private function prototypes -----------------------------------------------*/

void SystemClock_Config(void);

/* USER CODE BEGIN PFP */



/* USER CODE END PFP */



/* Private user code ---------------------------------------------------------*/

/* USER CODE BEGIN 0 */



/* USER CODE END 0 */



/**

* @brief The application entry point.

* @retval int

*/

int main(void)

{

/* USER CODE BEGIN 1 */



/* USER CODE END 1 */



/* MCU Configuration--------------------------------------------------------*/



/* Reset of all peripherals, Initializes the Flash interface and the Systick. */

HAL_Init();



/* USER CODE BEGIN Init */



/* USER CODE END Init */



/* Configure the system clock */

SystemClock_Config();



/* USER CODE BEGIN SysInit */



/* USER CODE END SysInit */



/* Initialize all configured peripherals */

MX_GPIO_Init();

MX_MEMORYMAP_Init();

MX_I2C1_Init();

/* USER CODE BEGIN 2 */

lcd_init();

/* USER CODE END 2 */



/* Infinite loop */

/* USER CODE BEGIN WHILE */

while (1)

{

/* USER CODE END WHILE */



/* USER CODE BEGIN 3 */

lcd_put_cursor(0,0);

lcd_send_string("hello word_1");

lcd_put_cursor(1,0);

lcd_send_string("hello word_2");

HAL_Delay(50);

}

/* USER CODE END 3 */

}



/**

* @brief System Clock Configuration

* @retval None

*/

void SystemClock_Config(void)

{

RCC_OscInitTypeDef RCC_OscInitStruct = {0};

RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};



/** Configure the main internal regulator output voltage

*/

if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK)

{

Error_Handler();

}



/** Initializes the CPU, AHB and APB buses clocks

*/

RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;

RCC_OscInitStruct.MSIState = RCC_MSI_ON;

RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;

RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_0;

RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;

RCC_OscInitStruct.PLL.PLLMBOOST = RCC_PLLMBOOST_DIV4;

RCC_OscInitStruct.PLL.PLLM = 3;

RCC_OscInitStruct.PLL.PLLN = 8;

RCC_OscInitStruct.PLL.PLLP = 2;

RCC_OscInitStruct.PLL.PLLQ = 2;

RCC_OscInitStruct.PLL.PLLR = 1;

RCC_OscInitStruct.PLL.PLLRGE = RCC_PLLVCIRANGE_1;

RCC_OscInitStruct.PLL.PLLFRACN = 0;

if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

{

Error_Handler();

}



/** Initializes the CPU, AHB and APB buses clocks

*/

RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2

|RCC_CLOCKTYPE_PCLK3;

RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV8;

RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

RCC_ClkInitStruct.APB3CLKDivider = RCC_HCLK_DIV1;



if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)

{

Error_Handler();

}

}



/* USER CODE BEGIN 4 */



/* USER CODE END 4 */



/**

* @brief This function is executed in case of error occurrence.

* @retval None

*/

void Error_Handler(void)

{

/* USER CODE BEGIN Error_Handler_Debug */

/* User can add his own implementation to report the HAL error return state */

__disable_irq();

while (1)

{

}

/* USER CODE END Error_Handler_Debug */

}



#ifdef USE_FULL_ASSERT

/**

* @brief Reports the name of the source file and the source line number

* where the assert_param error has occurred.

*  file: pointer to the source file name

*  line: assert_param error line source number

* @retval None

*/

void assert_failed(uint8_t *file, uint32_t line)

{

/* USER CODE BEGIN 6 */

/* User can add his own implementation to report the file name and line number,

ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

/* USER CODE END 6 */

}

#endif /* USE_FULL_ASSERT */

SMusc.1 · ‎2025-04-14

hi, I checked all the info:

1) connected the two pull two 10 K resistor between power supply and SCL/SDA pins

2) Checked the PINs on the LCD and on Nucleo board

3) Checked the data by using digital scope Tektronic as attached pictures

But on LCD still no character are showed.

I see a lot of noise on this kind of transmission.

What about the frequency of the pheriferal that i am using in clock configuration? Now is 16 MHz.

I am using many time this board for different project as complementary PWM ect and I never saw that kind distorted signal as in the picture. How fix the issue?

mƎALLEm · ‎2025-04-14

@SMusc.1 wrote:

What about the frequency of the pheriferal that i am using in clock configuration? Now is 16 MHz.

The peripheral clock or the system clock? better to share your ioc file.

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.

SMusc.1 · ‎2025-04-14

Hi, I just tried now to put the default frequency in the clock configuration and now is working well and all the charatcter i need are showed. Tks so much for the real good support.

Have nice day.

mƎALLEm · ‎2025-04-14

Thank you for the feedback. Could you please tell what do you mean by "the default frequency in the clock configuration"?

Could you please share the ioc file that could help others facing the same issue as yours?

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.

SMusc.1 · ‎2025-04-15

Hi, of course. When I started my project I followed one web tutorial and on that was using a different frequency clock. When I faced with my project instead I decided to left the default clock frequency in the clock configuration and this was the main issue i think. Attached the project.