/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body with PWM frequency sweep (35 kHz to 45 kHz)
******************************************************************************
* @attention
*
* Copyright (c) 2025 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 variables ---------------------------------------------------------*/
TIM_HandleTypeDef htim2;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_TIM2_Init(void);
void Update_PWM_Frequency(uint32_t frequency); // Function prototype for updating PWM frequency
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* 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--------------------------------------------------------*/
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_TIM2_Init();
/* Start PWM on TIM2 Channel 1 */
HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_1);
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
while (1)
{
/* Ramp up from 35 kHz to 45 kHz in steps of 250 Hz */
for (uint32_t pwm_frequency = 35000; pwm_frequency <= 45000; pwm_frequency += 250)
{
Update_PWM_Frequency(pwm_frequency);
HAL_Delay(50); // 50 ms delay per step
}
/* Ramp down from 45 kHz back to 35 kHz in steps of 250 Hz */
for (uint32_t pwm_frequency = 45000; pwm_frequency >= 35000; pwm_frequency -= 250)
{
Update_PWM_Frequency(pwm_frequency);
HAL_Delay(50); // 50 ms delay per step
}
}
}
/**
* @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_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);
/* Initializes the RCC Oscillators with HSI.
PLL is not used here, so the system clock remains HSI (assumed at 16 MHz) */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSIDiv = RCC_HSI_DIV1;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
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_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI; // Use HSI directly (16 MHz)
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief TIM2 Initialization Function
* @retval None
*
* The timer is initially configured for a 35 kHz PWM output.
* Calculation:
* - Timer clock (TIM_CLK) assumed at 16 MHz.
* - Period = (TIM_CLK / Desired Frequency) - 1
* - For 35 kHz: Period = (16,000,000 / 35000) - 1 ≈ 456.
*/
static void MX_TIM2_Init(void)
{
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_OC_InitTypeDef sConfigOC = {0};
htim2.Instance = TIM2;
htim2.Init.Prescaler = 0;
htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
htim2.Init.Period = (16000000 / 35000) - 1; // Initial PWM period for 35 kHz
htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
{
Error_Handler();
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_PWM_Init(&htim2) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
sConfigOC.OCMode = TIM_OCMODE_PWM1;
/* Set an initial pulse width of 50% duty cycle */
sConfigOC.Pulse = (htim2.Init.Period + 1) / 2;
sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
HAL_TIM_MspPostInit(&htim2);
}
/**
* @brief Updates the TIM2 PWM frequency while maintaining a 50% duty cycle.
* @param frequency: Desired PWM frequency in Hz (should be between 35 kHz and 45 kHz).
* @retval None
*/
void Update_PWM_Frequency(uint32_t frequency)
{
uint32_t tim_clk = 16000000; // Timer clock frequency (assumed 16 MHz)
uint32_t new_ARR = (tim_clk / frequency) - 1; // New auto-reload value
__HAL_TIM_SET_AUTORELOAD(&htim2, new_ARR);
__HAL_TIM_SET_COMPARE(&htim2, TIM_CHANNEL_1, (new_ARR + 1) / 2); // Maintain a 50% duty cycle
}
/**
* @brief GPIO Initialization Function
* @retval None
*/
static void MX_GPIO_Init(void)
{
/* Enable GPIOA clock */
__HAL_RCC_GPIOA_CLK_ENABLE();
}
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
__disable_irq();
while (1)
{
/* Optionally, add error indication code here */
}
}
#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 can add his own implementation to report the file name and line number */
}
#endif /* USE_FULL_ASSERT */