Question
Problem reading dht11 sensor data with stm32f429i-disc1.
Hi everyone. I am using a stm32f429i-disc1 board to read data from the dht11 sensor, but it cannot read the humidity and temperature.
I attach the code that I am using.
The screen displays "Hello world!", "Humidity: 0.0" and "Temp: 0.0", and when I use the stmstudio application to get a graph of each variable, I only get a 1 in the durum, mTime1, mTime2 variables. In the other variables they give 0.
I also have a stm32f407g board, with which this code is great, and with the stmstudio application I can see how the sensor works perfectly.
Anybody knows what could be the problem?
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "cmsis_os.h"
#include "crc.h"
#include "dma2d.h"
#include "i2c.h"
#include "ltdc.h"
#include "spi.h"
#include "tim.h"
#include "usart.h"
#include "usb_host.h"
#include "gpio.h"
#include "fmc.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "stdio.h"
#include "stm32f4xx_hal.h"
#include "stm32f429i_discovery_lcd.h"
#include "stm32f429i_discovery.h"
/* USER CODE END Includes */
/* USER CODE BEGIN PV */
TIM_HandleTypeDef htim7;
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
void MX_FREERTOS_Init(void);
/* 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(&htim7, 0);
while ((__HAL_TIM_GET_COUNTER(&htim7))<time);
}
void Set_Pin_Output (GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin)
{
GPIO_InitTypeDef DHT11_DATA = {0};
DHT11_DATA.Pin = GPIO_Pin;
DHT11_DATA.Mode = GPIO_MODE_OUTPUT_PP;
DHT11_DATA.Pull = GPIO_NOPULL;
DHT11_DATA.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOx, &DHT11_DATA);
}
void Set_Pin_Input (GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin)
{
GPIO_InitTypeDef DHT11_DATA = {0};
DHT11_DATA.Pin = GPIO_Pin;
DHT11_DATA.Mode = GPIO_MODE_INPUT;
DHT11_DATA.Pull = GPIO_NOPULL;
DHT11_DATA.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOx, &DHT11_DATA);
}
#define DHT11_PORT GPIOD
#define DHT11_PIN GPIO_PIN_15
uint8_t durum=0, Humidity=0, Temperature=0;
uint16_t tempVal=0, humVal=0;
uint8_t dhtVal[2];
uint8_t mData[40];
uint16_t mTime1=0, mTime2=0;
uint16_t mbit=0;
uint8_t parityVal=0,genParity=0;
uint8_t DHT11_Read (void)
{
for (int a=0;a<40;a++) mData[a]=0;
mTime1=0, mTime2=0, durum=0, tempVal=0, humVal=0, parityVal=0,genParity=0, mbit=0;
Set_Pin_Output (DHT11_PORT, DHT11_PIN);
HAL_GPIO_WritePin (DHT11_PORT, DHT11_PIN, GPIO_PIN_RESET);
delay (18000);
Set_Pin_Input(DHT11_PORT, DHT11_PIN);
__HAL_TIM_SET_COUNTER(&htim7, 0);
while (HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)==GPIO_PIN_SET) if((uint16_t)__HAL_TIM_GET_COUNTER(&htim7)> 500) return 0;
__HAL_TIM_SET_COUNTER(&htim7, 0);
while (HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)==GPIO_PIN_RESET) if((uint16_t)__HAL_TIM_GET_COUNTER(&htim7)> 500) return 0;
mTime1=(uint16_t)__HAL_TIM_GET_COUNTER(&htim7);
__HAL_TIM_SET_COUNTER(&htim7, 0);
while (HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)==GPIO_PIN_SET) if((uint16_t)__HAL_TIM_GET_COUNTER(&htim7)> 500) return 0;
mTime2=(uint16_t)__HAL_TIM_GET_COUNTER(&htim7);
if(mTime1<75 && mTime1>85 && mTime2<75 && mTime2>85){
return 0;
}
for(int j=0; j<40; j++){
__HAL_TIM_SET_COUNTER(&htim7, 0);
while (HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)==GPIO_PIN_RESET) if((uint16_t)__HAL_TIM_GET_COUNTER(&htim7)> 500) return 0;
__HAL_TIM_SET_COUNTER(&htim7, 0);
while (HAL_GPIO_ReadPin (DHT11_PORT, DHT11_PIN)==GPIO_PIN_SET) if((uint16_t)__HAL_TIM_GET_COUNTER(&htim7)> 500) return 0;
mTime1=(uint16_t)__HAL_TIM_GET_COUNTER(&htim7);
if(mTime1>20 && mTime1<30){
mbit=0;
}
else if (mTime1>60 && mTime1<80){
mbit=1;
}
mData[j]=mbit;
}
for(int i=0;i<8;i++){
humVal+=mData[i];
humVal=humVal<<1;
}
for(int i=16;i<24;i++){
tempVal+=mData[i];
tempVal=tempVal<<1;
}
for(int i=32;i<40;i++){
parityVal+=mData[i];
parityVal=parityVal<<1;
}
parityVal=parityVal>>1;
humVal=humVal>>1;
tempVal=tempVal>>1;
genParity= humVal + tempVal;
dhtVal[0]=tempVal;
dhtVal[1]=humVal;
return 1;
}
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
char str[50];
/* 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_FMC_Init();
MX_I2C3_Init();
MX_LTDC_Init();
MX_TIM1_Init();
MX_USART1_UART_Init();
MX_TIM7_Init();
MX_DMA2D_Init();
MX_SPI5_Init();
/* USER CODE BEGIN 2 */
HAL_TIM_Base_Start(&htim7);
BSP_LCD_Init();
BSP_LED_Init(LED3);
BSP_LED_Init(LED4);
/* Layer2 Init */
BSP_LCD_LayerDefaultInit(1, LCD_FRAME_BUFFER);
/* Set Foreground Layer */
BSP_LCD_SelectLayer(1);
/* Clear the LCD */
BSP_LCD_Clear(LCD_COLOR_WHITE);
BSP_LCD_SetColorKeying(1, LCD_COLOR_WHITE);
BSP_LCD_SetLayerVisible(1, DISABLE);
/* Layer1 Init */
BSP_LCD_LayerDefaultInit(0, LCD_FRAME_BUFFER + 0x130000);
/* Set Foreground Layer */
BSP_LCD_SelectLayer(0);
/* Enable The LCD */
BSP_LCD_DisplayOn();
/* Clear the LCD */
BSP_LCD_Clear(LCD_COLOR_GREEN);
BSP_LCD_DisplayStringAt(10, 10,(uint8_t*) "HELLO MELO!", LEFT_MODE);
durum=DHT11_Read();
if(durum==1){
Temperature=tempVal;
Humidity=humVal;
sprintf(str, "Humidity:%2.1f", (float)Humidity/ 10);
BSP_LCD_DisplayStringAt(0, 160,(uint8_t*) str, LEFT_MODE);
sprintf(str, "Temp:%2.1f", (float)Temperature/ 10);
BSP_LCD_DisplayStringAt(0, 200,(uint8_t*) str, LEFT_MODE);
}
HAL_Delay(1000);
/* USER CODE END 2 */
/* Call init function for freertos objects (in freertos.c) */
MX_FREERTOS_Init();
/* 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 */
}
/* USER CODE END 3 */
}