Can someone tell me what is the error in my code? (DHT11, STM32F429i-disc1)

[CMart.2]

I have the STM32F4291-disc1 microcontroller and the dht11 sensor that measures temperature and humidity. I'm trying to get the sensor to work, but I don't want the data (Temperature and humidity) on the screen and I don't know what could be wrong. My main.c code is as follows:

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2020 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under Ultimate Liberty license
  * SLA0044, the "License"; You may not use this file except in compliance with
  * the License. You may obtain a copy of the License at:
  *                             www.st.com/SLA0044
  *
  ******************************************************************************
  */
/* USER CODE END Header */
 
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "cmsis_os.h"
#include "usb_host.h"
 
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "i2c-lcd.h"
#include "stdio.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 ---------------------------------------------------------*/
CRC_HandleTypeDef hcrc;
 
DMA2D_HandleTypeDef hdma2d;
 
I2C_HandleTypeDef hi2c3;
 
LTDC_HandleTypeDef hltdc;
 
SPI_HandleTypeDef hspi5;
 
TIM_HandleTypeDef htim1;
TIM_HandleTypeDef htim6;
 
UART_HandleTypeDef huart1;
 
SDRAM_HandleTypeDef hsdram1;
 
osThreadId defaultTaskHandle;
/* USER CODE BEGIN PV */
 
/* USER CODE END PV */
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CRC_Init(void);
static void MX_DMA2D_Init(void);
static void MX_FMC_Init(void);
static void MX_I2C3_Init(void);
static void MX_LTDC_Init(void);
static void MX_SPI5_Init(void);
static void MX_TIM1_Init(void);
static void MX_USART1_UART_Init(void);
static void MX_TIM6_Init(void);
void StartDefaultTask(void const * argument);
 
/* USER CODE BEGIN PFP */
 
/* USER CODE END PFP */
 
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
void delay (uint16_t time)
{
	/* change your code here for the delay in microseconds */
	__HAL_TIM_SET_COUNTER(&htim6, 0);
	while ((__HAL_TIM_GET_COUNTER(&htim6))<time);
}
 
void Display_Temp (float Temp)
{
	char str[20] = {0};
	lcd_put_cur(0, 0);
 
	sprintf (str, "TEMP:- %.2f ", Temp);
	lcd_send_string(str);
	lcd_send_data('C');
}
 
void Display_Rh (float Rh)
{
	char str[20] = {0};
	lcd_put_cur(1, 0);
 
	sprintf (str, "RH:- %.2f ", Rh);
	lcd_send_string(str);
	lcd_send_data('%');
}
 
uint8_t Rh_byte1, Rh_byte2, Temp_byte1, Temp_byte2;
uint16_t SUM, RH, TEMP;
 
float Temperature = 0;
float Humidity = 0;
uint8_t Presence = 0;
 
void Set_Pin_Output (GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin)
{
	GPIO_InitTypeDef GPIO_InitStruct = {0};
	GPIO_InitStruct.Pin = GPIO_Pin;
	GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
	GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
	HAL_GPIO_Init(GPIOx, &GPIO_InitStruct);
}
 
void Set_Pin_Input (GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin)
{
	GPIO_InitTypeDef GPIO_InitStruct = {0};
	GPIO_InitStruct.Pin = GPIO_Pin;
	GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
	GPIO_InitStruct.Pull = GPIO_PULLUP;
	HAL_GPIO_Init(GPIOx, &GPIO_InitStruct);
}
 
#define DHT11_PORT GPIOC
#define DHT11_PIN GPIO_PIN_3
 
void DHT11_Start (void)
{
	Set_Pin_Output (DHT11_PORT, DHT11_PIN);  // set the pin as output
	HAL_GPIO_WritePin (DHT11_PORT, DHT11_PIN, 0);   // pull the pin low
	delay (18000);   // wait for 18ms
    HAL_GPIO_WritePin (DHT11_PORT, DHT11_PIN, 1);   // pull the pin high
	delay (20);   // wait for 20us
	Set_Pin_Input(DHT11_PORT, DHT11_PIN);    // set as input
}
 
uint8_t DHT11_Check_Response (void)
{
	uint8_t Response = 0;
	delay (40);
	if (!(HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)))
	{
		delay (80);
		if ((HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN))) Response = 1;
		else Response = -1; // 255
	}
	while ((HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)));   // wait for the pin to go low
 
	return Response;
}
 
uint8_t DHT11_Read (void)
{
	uint8_t i,j;
	for (j=0;j<8;j++)
	{
		while (!(HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)));   // wait for the pin to go high
		delay (40);   // wait for 40 us
		if (!(HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)))   // if the pin is low
		{
			i&= ~(1<<(7-j));   // write 0
		}
		else i|= (1<<(7-j));  // if the pin is high, write 1
		while ((HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)));  // wait for the pin to go low
	}
	return i;
}
/* 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_CRC_Init();
  MX_DMA2D_Init();
  MX_FMC_Init();
  MX_I2C3_Init();
  MX_LTDC_Init();
  MX_SPI5_Init();
  MX_TIM1_Init();
  MX_USART1_UART_Init();
  MX_TIM6_Init();
  /* USER CODE BEGIN 2 */
  HAL_TIM_Base_Start(&htim6);
 
  lcd_init();
  lcd_send_string("INITIALISING>>>>");
  HAL_Delay(2000);
  lcd_clear ();
  /* USER CODE END 2 */
 
  /* USER CODE BEGIN RTOS_MUTEX */
  /* add mutexes, ... */
  /* USER CODE END RTOS_MUTEX */
 
  /* USER CODE BEGIN RTOS_SEMAPHORES */
  /* add semaphores, ... */
  /* USER CODE END RTOS_SEMAPHORES */
 
  /* USER CODE BEGIN RTOS_TIMERS */
  /* start timers, add new ones, ... */
  /* USER CODE END RTOS_TIMERS */
 
  /* USER CODE BEGIN RTOS_QUEUES */
  /* add queues, ... */
  /* USER CODE END RTOS_QUEUES */
 
  /* Create the thread(s) */
  /* definition and creation of defaultTask */
  osThreadDef(defaultTask, StartDefaultTask, osPriorityNormal, 0, 4096);
  defaultTaskHandle = osThreadCreate(osThread(defaultTask), NULL);
 
  /* USER CODE BEGIN RTOS_THREADS */
  /* add threads, ... */
  /* USER CODE END RTOS_THREADS */
 
  /* Start scheduler */
  osKernelStart();
 
  /* We should never get here as control is now taken by the scheduler */
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
	  Display_Temp(Temperature);
	  Display_Rh(Humidity);
 
	  DHT11_Start();
	  	  Presence = DHT11_Check_Response();
	  	  Rh_byte1 = DHT11_Read ();
	  	  Rh_byte2 = DHT11_Read ();
	  	  Temp_byte1 = DHT11_Read ();
	  	  Temp_byte2 = DHT11_Read ();
	  	  SUM = DHT11_Read();
 
	  	  TEMP = Temp_byte1;
	  	  RH = Rh_byte1;
 
	  	  Temperature = (float) TEMP;
	  	  Humidity = (float) RH;
  }
  /* USER CODE END 3 */
}

[CMart.2]

When compiling it does not give me any error.

[S.Ma]

Can't you share the values for *_bytes1/2 ? Any information helps find the root cause.

[CMart.2]

Hi. Thanks for answering. I'm a beginner and I don't know what you mean by * _bytes1 / 2

[CMart.2]

If it helps you, also added a couple of files apart from the default ones.

i2c-lcd.c

/** Put this in the src folder **/
 
#include "i2c-lcd.h"
extern I2C_HandleTypeDef hi2c3;  // change your handler here accordingly
 
#define SLAVE_ADDRESS_LCD 0x4E // change this according to your setup
 
void lcd_send_cmd (char cmd)
{
  char data_u, data_l;
	uint8_t data_t[4];
	data_u = (cmd&0xf0);
	data_l = ((cmd<<4)&0xf0);
	data_t[0] = data_u|0x0C;  //en=1, rs=0
	data_t[1] = data_u|0x08;  //en=0, rs=0
	data_t[2] = data_l|0x0C;  //en=1, rs=0
	data_t[3] = data_l|0x08;  //en=0, rs=0
	HAL_I2C_Master_Transmit (&hi2c3, SLAVE_ADDRESS_LCD,(uint8_t *) data_t, 4, 100);
}
 
void lcd_send_data (char data)
{
	char data_u, data_l;
	uint8_t data_t[4];
	data_u = (data&0xf0);
	data_l = ((data<<4)&0xf0);
	data_t[0] = data_u|0x0D;  //en=1, rs=0
	data_t[1] = data_u|0x09;  //en=0, rs=0
	data_t[2] = data_l|0x0D;  //en=1, rs=0
	data_t[3] = data_l|0x09;  //en=0, rs=0
	HAL_I2C_Master_Transmit (&hi2c3, SLAVE_ADDRESS_LCD,(uint8_t *) data_t, 4, 100);
}
 
void lcd_clear (void)
{
	lcd_send_cmd(0x01);
	HAL_Delay(10);
}
 
void lcd_put_cur(int row, int col)
{
    switch (row)
    {
        case 0:
            col |= 0x80;
            break;
        case 1:
            col |= 0xC0;
            break;
    }
 
    lcd_send_cmd (col);
}
 
 
void lcd_init (void)
{
	// 4 bit initialisation
	HAL_Delay(50);  // wait for >40ms
	lcd_send_cmd (0x30);
	HAL_Delay(5);  // wait for >4.1ms
	lcd_send_cmd (0x30);
	HAL_Delay(1);  // wait for >100us
	lcd_send_cmd (0x30);
	HAL_Delay(10);
	lcd_send_cmd (0x20);  // 4bit mode
	HAL_Delay(10);
 
  // dislay initialisation
	lcd_send_cmd (0x28); // Function set --> DL=0 (4 bit mode), N = 1 (2 line display) F = 0 (5x8 characters)
	HAL_Delay(1);
	lcd_send_cmd (0x08); //Display on/off control --> D=0,C=0, B=0  ---> display off
	HAL_Delay(1);
	lcd_send_cmd (0x01);  // clear display
	HAL_Delay(1);
	HAL_Delay(1);
	lcd_send_cmd (0x06); //Entry mode set --> I/D = 1 (increment cursor) & S = 0 (no shift)
	HAL_Delay(1);
	lcd_send_cmd (0x0C); //Display on/off control --> D = 1, C and B = 0. (Cursor and blink, last two bits)
}
 
void lcd_send_string (char *str)
{
	while (*str) lcd_send_data (*str++);
}

i2c-lcd.h

#include "stm32f4xx_hal.h"
 
void lcd_init (void);   // initialize lcd
 
void lcd_send_cmd (char cmd);  // send command to the lcd
 
void lcd_send_data (char data);  // send data to the lcd
 
void lcd_send_string (char *str);  // send string to the lcd
 
void lcd_put_cur(int row, int col);  // put cursor at the entered position row (0 or 1), col (0-15);
 
void lcd_clear (void);

[Tesla DeLorean]

The Rh_byte1, Rh_byte2, Temp_byte1 and Temp_byte2 values your code actually succeeds in reading..

[Tesla DeLorean]

So? Compilers can't tell if your logic or thoughts are broken, only if the code looks syntactically correct.

Confirm the signal timings and responses with a scope or logic analyzer.

[CMart.2]

I don't know if you read them successfully, because the screen appears blank and does not show any value.

[CMart.2]

Can you name me some scope or logic analyzer?

[CMart.2]

I think there is something wrong with my logic, but I don't know what it is