© ArduTV 2025
A simple distance meter using STM Nucleo board and the HC-SR04 ultrasonic sensor.
In this simple simple example we use one STM NUCLEo board (STM32-F401RE) , the ArduTV and one sensor HC-SR04.
The output of the sensor is shown on television using ArduTV.HC-SR04 connections:
+5V --> +5V
GND--> GND
Trig --> D4
Echo--> D5
PLEASE WATCH THE PICTURES AND VIDEO AT THE END OF THE PAGE.
The code of the example
(Please note that part of this code is automatically generated by STM32CubeIDE, as used with this tool)
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2024 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"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "Ardutv.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 ---------------------------------------------------------*/
SPI_HandleTypeDef hspi1;
TIM_HandleTypeDef htim1;
UART_HandleTypeDef huart2;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_SPI1_Init(void);
static void MX_TIM1_Init(void);
/* USER CODE BEGIN PFP */
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
PUTCHAR_PROTOTYPE
{
/* Place your implementation of fputc here */
/* e.g. write a character to the USART1 and Loop until the end of transmission */
HAL_UART_Transmit(&huart2, (uint8_t *)&ch, 1, 0xFFFF);
return ch;
}
void DelayUS(uint32_t us) {
uint32_t durat = us * 16;
TIM1->CNT=0;
while (TIM1->CNT < durat);
}
/* 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 */
static uint8_t runonce = 0;
float distance;
int duration_i,distance_i;
char car[3];
/* 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_USART2_UART_Init();
MX_SPI1_Init();
MX_TIM1_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, 1);
HAL_Delay(1000);
//char data[] = {"Hey Universe\n\r"};
HAL_TIM_Base_Start(&htim1);
int PinState=0;
ATV_BGColor(0,0,61);
ATV_PenColor(61,20,0);
ATV_Clear();
ATV_printString("ArduTV with ST NUCLEO Board", 60, 80,2);
ATV_PenColor(61,10,0);
ATV_printString("Distance measurement example", 60, 400,1);
ATV_printString("0.00m", 50, 360,1);
ATV_printString("6.51m", 490, 360,1);
ATV_Rect(67,318,444,35,0);
ATV_PenColor(31,30,10);
ATV_printString("Distance:", 80, 200,3);
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
if (runonce != 1)
{
printf("Hello World\n\r");
duration_i=0;
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, 0);//D4
DelayUS(2);
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, 1);
DelayUS(20);
//printf("Ready\n\r");
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, 0);
while(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_4)!=GPIO_PIN_SET);// da cambiare //D5
PinState=HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_4);
// printf("Read\n\r");
while(PinState!=GPIO_PIN_RESET)
{
duration_i++;
//DelayUS(1);
if (duration_i>38000)
break;
PinState=HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_4);
PinState=HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_4); //Added just for "calibration"
//PinState=1;
}
printf("Exit\n\r");
printf("Duration: %d \n\r",duration_i);
distance=(duration_i*.0343)/2;
//distance_i=distance;
printf("Distance: %f \n\r",distance);
distance_i=distance*1;
ATV_PenColor(0,0,61);
ATV_Rect(70,320,440,30,1);
ATV_PenColor(31,30,10);
ATV_Rect(70,320,distance_i/1.5,30,1);
car[0]=distance_i/100+48;
distance_i%=100;
car[1]=(distance_i)/10+48;
distance_i%=10;
car[2]=distance_i+48;
ATV_printchar(car[0], 240+(5*8*0), 230,5);
ATV_printchar('.', 240+(5*8*1), 230,5);
ATV_printchar(car[1], 240+(5*8*2), 230,5);
ATV_printchar(car[2], 240+(5*8*3), 230,5);
ATV_printchar('m', 240+(5*8*4), 230,5);
HAL_Delay(50);
//runonce = 1;
}
}
/* 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
*/
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLM = 16;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
RCC_OscInitStruct.PLL.PLLQ = 7;
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_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief SPI1 Initialization Function
* @param None
* @retval None
*/
static void MX_SPI1_Init(void)
{
/* USER CODE BEGIN SPI1_Init 0 */
/* USER CODE END SPI1_Init 0 */
/* USER CODE BEGIN SPI1_Init 1 */
/* USER CODE END SPI1_Init 1 */
/* SPI1 parameter configuration*/
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_MASTER;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_16BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_128;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN SPI1_Init 2 */
/* USER CODE END SPI1_Init 2 */
}
/**
* @brief TIM1 Initialization Function
* @param None
* @retval None
*/
static void MX_TIM1_Init(void)
{
/* USER CODE BEGIN TIM1_Init 0 */
/* USER CODE END TIM1_Init 0 */
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
/* USER CODE BEGIN TIM1_Init 1 */
/* USER CODE END TIM1_Init 1 */
htim1.Instance = TIM1;
htim1.Init.Prescaler = 5;
htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
htim1.Init.Period = 65535;
htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim1.Init.RepetitionCounter = 0;
htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
{
Error_Handler();
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM1_Init 2 */
/* USER CODE END TIM1_Init 2 */
}
/**
* @brief USART2 Initialization Function
* @param None
* @retval None
*/
static void MX_USART2_UART_Init(void)
{
/* USER CODE BEGIN USART2_Init 0 */
/* USER CODE END USART2_Init 0 */
/* USER CODE BEGIN USART2_Init 1 */
/* USER CODE END USART2_Init 1 */
huart2.Instance = USART2;
huart2.Init.BaudRate = 115200;
huart2.Init.WordLength = UART_WORDLENGTH_8B;
huart2.Init.StopBits = UART_STOPBITS_1;
huart2.Init.Parity = UART_PARITY_NONE;
huart2.Init.Mode = UART_MODE_TX_RX;
huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart2.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART2_Init 2 */
/* USER CODE END USART2_Init 2 */
}
/**
* @brief GPIO Initialization Function
* @param None
* @retval None
*/
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOB, US_Output_Pin|GPIO_PIN_6, GPIO_PIN_RESET);
/*Configure GPIO pin : B1_Pin */
GPIO_InitStruct.Pin = B1_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(B1_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : US_Input_Pin */
GPIO_InitStruct.Pin = US_Input_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(US_Input_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : US_Output_Pin */
GPIO_InitStruct.Pin = US_Output_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(US_Output_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : PB6 */
GPIO_InitStruct.Pin = GPIO_PIN_6;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}
/* 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.
* @param file: pointer to the source file name
* @param 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 */
Some pictures of the project
TV Output
The Used HW
The distance is displayed as number and as a bar.
All HW Connected
© ArduTV 2025