Measuring Clock Frequency

ctanto333 · ‎2025-02-14

I am traying to meassure a clcok frequency using STM32F103C8T6 board i am unable to capture. Please anyone solve my problem. This is the code i am using.


#include "main.h"
#include <stdio.h>
#include <string.h>

#define IDLE   0
#define DONE   1
#define F_CLK  72000000UL  // System clock frequency for STM32F1xx

volatile uint8_t state = IDLE;
volatile uint8_t message[50] = {'\0'};  // Message buffer
volatile uint32_t T1 = 0;  // First capture
volatile uint32_t T2 = 0;  // Second capture
volatile uint32_t ticks = 0;  // Time difference
volatile uint16_t TIM2_OVC = 0;  // Timer overflow counter
volatile uint32_t frequency = 0;  // Calculated frequency

TIM_HandleTypeDef htim2;
UART_HandleTypeDef huart1;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_TIM2_Init(void);
static void MX_USART1_UART_Init(void);

int main(void)
{
    HAL_Init();  // Initialize HAL
    SystemClock_Config();  // Configure the system clock

    MX_GPIO_Init();  // Initialize GPIO
    MX_TIM2_Init();  // Initialize Timer 2
    MX_USART1_UART_Init();  // Initialize UART1

    // Start timer and input capture interrupts
    HAL_TIM_Base_Start_IT(&htim2);  // Start timer overflow interrupt
    HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_1);  // Start input capture on channel 1

    while (1)
    {
        // Main loop does nothing, frequency is measured in interrupts
    }
}

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef* htim)
{
    if (htim->Instance == TIM2 && htim->Channel == HAL_TIM_ACTIVE_CHANNEL_1)
    {
        if (state == IDLE)
        {
            T1 = TIM2->CCR1;  // Capture first time
            TIM2_OVC = 0;  // Reset overflow counter
            state = DONE;
        }
        else if (state == DONE)
        {
            T2 = TIM2->CCR1;  // Capture second time
            ticks = (T2 + (TIM2_OVC * 65536)) - T1;  // Calculate elapsed ticks
            if (ticks > 10)  // Ignore very small intervals
            {
                frequency = (uint32_t)(F_CLK / ticks);  // Calculate frequency
                sprintf((char*)message, "Frequency = %lu Hz\n\r", frequency);
                //HAL_UART_Transmit(&huart1, message, strlen((char*)message), 100);  // Transmit frequency
                HAL_UART_Transmit(&huart1, (uint8_t*)message, strlen((char*)message), 100);
            }
            state = IDLE;  // Reset state
        }
    }
}

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef* htim)
{
    if (htim->Instance == TIM2)
    {
        TIM2_OVC++;  // Increment overflow counter
    }
}

void SystemClock_Config(void)
{
    RCC_OscInitTypeDef RCC_OscInitStruct = {0};
    RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

    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();
    }

    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();
    }
}

static void MX_TIM2_Init(void)
{
    TIM_ClockConfigTypeDef sClockSourceConfig = {0};
    TIM_MasterConfigTypeDef sMasterConfig = {0};
    TIM_IC_InitTypeDef sConfigIC = {0};

    htim2.Instance = TIM2;
    htim2.Init.Prescaler = 0;
    htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim2.Init.Period = 65535;
    htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
    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_IC_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();
    }
    sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
    sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
    sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
    sConfigIC.ICFilter = 0;
    if (HAL_TIM_IC_ConfigChannel(&htim2, &sConfigIC, TIM_CHANNEL_1) != HAL_OK)
    {
        Error_Handler();
    }
}

static void MX_USART1_UART_Init(void)
{
    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();
    }
}

static void MX_GPIO_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};

    __HAL_RCC_GPIOA_CLK_ENABLE();  // Enable GPIOA clock

    // Configure PA0 as TIM2_CH1 input
    GPIO_InitStruct.Pin = GPIO_PIN_0;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

void Error_Handler(void)
{
    __disable_irq();
    while (1)
    {
    }
}

MM..1 · ‎2025-02-14

Why not debug your code first? Check if is braek in

HAL_TIM_IC_CaptureCallback