How to display the value of GPIO_ReadPin quickly and correctly on STM32F103C8T6 ?

[BangDuLzGG]

Dear Members,

How can the speed of displaying the value of HAL_GPIO_ReadPin when reading a pwm signal be equivalent to the speed of displaying the value in another variable located outside WHILE ?

I made a code to read the pwm signal to find out whether the pwm signal is in high mode or low mode using HAL_GPIO_ReadPin. When mode is high it will send a value of 1 and when mode is low it will send a value of 0.

I tested it by reading a 1Hz frequency which has a duty cycle that changes every second starting from 10%, 30%, 50% and I set a delay of 100ms on WHILE.

When I looked at the code output with UART, I saw that the time value in high mode for each duty cycle that the program read was correct.

However, the number of values 1 appearing when reading one duty cycle does not correspond to the size of the duty cycle being read. Here are the results of the code output:

DUTY CYCLE 10%

[10:01:46:124] 1C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:225] 1C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:326] 1C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:427] 0C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:528] 0C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:629] 0C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:730] 0C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:831] 0C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:46:932] 0C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

[10:01:47:033] 0C | Ton_ms: 00099.90 | Ton_us: 99899.98 ␍␊

DUTY CYCLE 30%

[10:01:47:134] 1C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:235] 1C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:336] 1C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:437] 1C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:538] 1C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:639] 0C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:740] 0C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:841] 0C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:47:942] 0C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

[10:01:48:043] 0C | Ton_ms: 00299.92 | Ton_us: 299922.22 ␍␊

DUTY CYCLE 50%

[10:01:48:144] 1C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:245] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:346] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:447] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:548] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:649] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:750] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:851] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:48:952] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

[10:01:49:053] 0C | Ton_ms: 00499.94 | Ton_us: 499944.41 ␍␊

In the output display above, it is found that 1C is displayed as follows:
• Duty cycle 10% = 1C appears 3x
• Duty cycle 30% = 1C appears 5x
• Duty cycle 50% = 1C appears 1x

The output should display 1C as much as:
• Duty cycle 10% = 1C appears 1x
• Duty cycle 30% = 1C appears 3x
• Duty cycle 50% = 1C appears 5x

So, the appearance of the 1C status is not correct for every type of duty cycle that exists.

How do I ensure that the appearance of 1C matches each duty cycle reading that the code is reading?

This is the STM32CUBEIDE program that I made.

/* 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"
#include "stdio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* 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 ---------------------------------------------------------*/
TIM_HandleTypeDef htim3;

UART_HandleTypeDef huart1;

/* USER CODE BEGIN PV */


uint32_t IC_direct_mode_periode = 0;
uint32_t IC_indirect_mode_Ton   = 0;
uint32_t nilai_prescaler        = 1999;
uint32_t untuk_rumus_frekuensi  = 18000;
float    untuk_rumus_waktu_Ton  = 0.017998;

float    duty_cycle   = 0;
float    frekuensi 	  = 0;
float    waktu_Ton_us = 0;
float    waktu_Ton_ms = 0;
float    waktu_Ton_s  = 0;
char     status[1000];

uint32_t    status_pin3;
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_TIM3_Init(void);
static void MX_USART1_UART_Init(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_TIM3_Init();
  MX_USART1_UART_Init();
  /* USER CODE BEGIN 2 */
  HAL_TIM_IC_Start_IT(&htim3, TIM_CHANNEL_1);
  HAL_TIM_IC_Start_IT(&htim3, TIM_CHANNEL_2);
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {

	  //BACA SINYAL PWM 3 DI PIN A3
	  if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_3) == GPIO_PIN_SET)
		 {
		  status_pin3 = 1;
		 }

		  if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_3) == GPIO_PIN_RESET)
			{
			  status_pin3 = 0;
			}
			/* USER CODE END WHILE */
			  sprintf(status, "%luC | Ton_ms: %08.2f | Ton_us: %08.2f \r\n", status_pin3, waktu_Ton_ms, waktu_Ton_us);
			  HAL_UART_Transmit_IT(&huart1, status, strlen(status));

			  frekuensi  = 0;
			  duty_cycle = 0;

			  HAL_Delay(100);
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  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_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief TIM3 Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_TIM3_Init(void)
{

  /* USER CODE BEGIN TIM3_Init 0 */

  /* USER CODE END TIM3_Init 0 */

  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_SlaveConfigTypeDef sSlaveConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_IC_InitTypeDef sConfigIC = {0};

  /* USER CODE BEGIN TIM3_Init 1 */
  /* USER CODE END TIM3_Init 1 */
  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 0;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 65535;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_TIM_IC_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }
  sSlaveConfig.SlaveMode = TIM_SLAVEMODE_RESET;
  sSlaveConfig.InputTrigger = TIM_TS_TI1FP1;
  sSlaveConfig.TriggerPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
  sSlaveConfig.TriggerFilter = 0;
  if (HAL_TIM_SlaveConfigSynchro(&htim3, &sSlaveConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
  sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
  sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
  sConfigIC.ICFilter = 0;
  if (HAL_TIM_IC_ConfigChannel(&htim3, &sConfigIC, TIM_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_FALLING;
  sConfigIC.ICSelection = TIM_ICSELECTION_INDIRECTTI;
  if (HAL_TIM_IC_ConfigChannel(&htim3, &sConfigIC, TIM_CHANNEL_2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM3_Init 2 */

  /* USER CODE END TIM3_Init 2 */

}

/**
  * @brief USART1 Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_USART1_UART_Init(void)
{

  /* USER CODE BEGIN USART1_Init 0 */

  /* USER CODE END USART1_Init 0 */

  /* USER CODE BEGIN USART1_Init 1 */

  /* USER CODE END USART1_Init 1 */
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART1_Init 2 */

  /* USER CODE END USART1_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_GPIOD_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

  /*Configure GPIO pins : Baca_Sinyal_3_XOR_Pin Baca_Sinyal_1_Pin Baca_Sinyal_2_Pin */
  GPIO_InitStruct.Pin = Baca_Sinyal_3_XOR_Pin|Baca_Sinyal_1_Pin|Baca_Sinyal_2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
		  if (htim->Channel == HAL_TIM_ACTIVE_CHANNEL_1)
		  {

			//mendapatkan nilai input capture dari channel 1 yang merupakan direct mode untuk periode
			IC_direct_mode_periode = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_1);

			if (IC_direct_mode_periode != 0)
			{
				//mendapatkan nilai input capture dari channel 2 yang merupakan indirect mode untuk Ton
				IC_indirect_mode_Ton = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_2);

				//rumus frekuensi
				frekuensi = (float) untuk_rumus_frekuensi / IC_direct_mode_periode;

			  if (frekuensi > 500) //jika frekuensi lebih dari 500Hz, maka
			  	  {
			        nilai_prescaler 	  = 0;        //ubah prescaler menjadi 0 untuk pembacaan frekuensi lebih tinggi
			        untuk_rumus_frekuensi = 36000000; //ubah rumus menjadi 36Mhz untuk pembacaan frekuensi lebih tinggi
			        untuk_rumus_waktu_Ton = 35.95;	  //ubah rumus menjadi 35.95 untuk pembacaan frekuensi lebih tinggi
			      }

			  	  else //jika frekuensi tidak lebih dari 500Hz, maka
			  	  {
			        nilai_prescaler 	  = 1999;     //ubah prescaler menjadi 1999 untuk pembacaan frekuensi lebih rendah
			        untuk_rumus_frekuensi = 18000;    //ubah rumus menjadi 18Khz untuk pembacaan frekuensi lebih rendah
			        untuk_rumus_waktu_Ton = 0.017998; //ubah rumus menjadi 0.017998 untuk pembacaan frekuensi lebih rendah
			      }

			  TIM3->PSC = nilai_prescaler; //nilai prescaler akan sama dengan isi "nilai_prescaler"

			  //rumus duty cycle
			  duty_cycle = (float)(IC_indirect_mode_Ton * 100) / IC_direct_mode_periode;

			  //rumus waktu Ton "HIGH" dalam detik
			  waktu_Ton_us = IC_indirect_mode_Ton / untuk_rumus_waktu_Ton;

			  //rumus waktu Ton "HIGH" dalam milidetik
			  waktu_Ton_ms = waktu_Ton_us / 1000;

			  //rumus waktu Ton "HIGH" dalam mikrodetik
			  waktu_Ton_s = waktu_Ton_ms / 1000;

			}

			else
			{
			  duty_cycle = 0;
			  frekuensi = 0;
			  waktu_Ton_us = 0;
			  waktu_Ton_ms = 0;
			}
		  }
}


/* 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 */

[Sarra.S]

Hello @BangDuLzGG, thank you for your question 

For a 1Hz PWM signal, a 100ms delay in your while loop is too long 

also, Instead of using HAL_GPIO_ReadPin in a while loop with a delay, consider using timer interrupts to capture the PWM signal

[Tesla DeLorean · Accepted solution]

You can use a TIM CH1/CH2 to record period and duty/phase in TIM count units via PWM Input Capture mode.