stm32hcsr04Hal

STM32 HAL Library Implementation for HC-SR04 Ultrasonic Sensor
Overview of the HC-SR04 Module Integration with STM32 Using HAL Library
The integration process involves configuring specific peripherals on the STM32 microcontroller to interact effectively with the HC-SR04 module, ensuring accurate distance measurements between 2 cm and 600 cm are achieved[^3]. The configuration includes setting up GPIO pins for trigger signal generation and echo pulse reception.
Configuration Steps via STM32CubeMX
To begin, open STM32CubeMX software:

Select STM32F103C8T6 as the target device.
Configure RCC (Reset and Clock Control).
Set up UART or USART interfaces if serial communication is required alongside measurement data transmission.
Initialize TIM3 timer peripheral specifically configured to output a 10 µs high-level pulse needed by the HC-SR04's Trig pin[^4].
Designate appropriate GPIO pins connected to the Echo line from the sensor; these will be set as input type.

Example Code Snippet Demonstrating Initialization and Measurement Functionality
Below demonstrates how one might initialize necessary components within main.c file after generating project files through CubeMX tool:
#include "stm32f1xx_hal.h"

// Define global variables used across functions
extern uint32_t TimeHigh;
extern uint32_t Distance;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_TIM3_Init(void);

int main(void){
/* Reset of all peripherals, Initializes the Flash interface and Systick */
HAL_Init();

/* Configure the system clock */
SystemClock_Config();

/* Initialize all configured peripherals */
MX_GPIO_Init(); // For TRIG & ECHO lines setup
MX_TIM3_Init(); // To generate pulses

while(1){
MeasureDistance(&htim3); // Custom function defined later

// Add delay here before next reading cycle starts
HAL_Delay(500);

printf("Measured Distance: %lu cm\n", Distance / 58); // Assuming speed of sound at ~340m/s
}
}

/**
* @brief This function measures time duration during which ECHO remains HIGH,
* calculates corresponding distance based upon this value using formula d=vt where v=speed_of_sound_in_air
*
* @param htim Pointer to a TIM_HandleTypeDef structure that contains
* the configuration information for TIM module.
*/
void MeasureDistance(TIM_HandleTypeDef* htim){
__HAL_TIM_SET_COUNTER(htim, 0); // Reset counter register prior starting new measurement sequence

HAL_GPIO_WritePin(TRIGGER_PORT, TRIGGER_PIN, SET); // Send short positive edge (~10us wide)
HAL_DelayMicroseconds(10);
HAL_GPIO_WritePin(TRIGGER_PORT, TRIGGER_PIN, RESET);

// Wait until rising edge detected then start counting...
while(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_UPDATE) != RESET){};

TimeHigh = __HAL_TIM_GET_COUNTER(htim); // Read elapsed ticks when falling-edge occurs

// Calculate actual traveled path length divided two since round-trip considered above
Distance = ((TimeHigh * 0.0343) / 2);
}
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This example assumes certain definitions (TRIGGER_PORT, TRIGGER_PIN) have been made elsewhere in your program according to hardware connections established between MCU and sensor modules.
--related questions--

How does changing environmental temperature affect accuracy in measuring distances using an ultrasonic sensor like HC-SR04?
What modifications would you make to support multiple HC-SR04 sensors operating simultaneously without interference issues?
Can we improve response times further than what has been demonstrated? If yes, suggest methods applicable under typical conditions found inside indoor environments.
Is it possible to integrate this solution into larger systems involving wireless communications protocols such as Bluetooth Low Energy (BLE)?
Are there any alternative approaches available besides utilizing timers directly linked with interrupts for capturing precise timing intervals related to echo signals received back from objects being measured against?