I'm working on a project where I need to generate a pulse with a desired frequency, which can be adjusted through three different modes.

The modes are as follows:

• Frequency remains the same.
• Frequency is divided by 2.
• Frequency is multiplied by 2.

The mode is selected using a switch (configured for external interrupt callback), and the pulse is generated using Timer 4 (clock 48 MHz, prescaler 4800) in Output Compare mode with the "toggle on match" feature. The ARR (Auto-Reload Register) and CCR (Capture/Compare Register) values are set based on the output from a rotary encoder.

The pulse generation itself works as expected, but when switching between modes, the signal goes high for a fixed period of time (8 seconds) before returning to the expected pulse pattern.

Has anyone encountered a similar issue? What could be the possible reasons for this behavior, and how can I address it?

    while (1)
    {
        Rotary_Enc_Chk();

        if(rotChk == TRUE)
        {
            rotChk = FALSE;

            sprintf(txBuffer, "Speed: %d\n\r", speed);
            HAL_UART_Transmit(&huart1, (uint8_t*)txBuffer, strlen(txBuffer), 10);
            TM1637_DisplayDecimal(speed, 0);                                        
            if(speed > 0)
            {
                uint16_t freq = (10000 / (2 * xFactor * speed )) - 1;
                //uint16_t freq = speed;
                TIM14->ARR = freq;
                TIM14->CCR1 = freq;
                HAL_TIM_OC_Start(&htim14, TIM_CHANNEL_1);
            }
            else {
                sprintf(txBuffer, "Speed: %d\n\r", speed);
                HAL_UART_Transmit(&huart1, (uint8_t*)txBuffer, strlen(txBuffer), 10);
            }
        }

        if(modeChange == TRUE)
        {
            sprintf(txBuffer, "Mode: %d\n\r", speed);
            HAL_UART_Transmit(&huart1, (uint8_t*)txBuffer, strlen(txBuffer), 10);
            rotChk = TRUE;
            modeChange = FALSE;
            Mode_Check();
        }

void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
    UNUSED(GPIO_Pin);

    if((GPIO_Pin == _2X_SEL_Pin) || (GPIO_Pin == X_2_SEL_Pin))
    {
        modeChange = TRUE;
    }

void Mode_Check()
{
    if(HAL_GPIO_ReadPin(GPIOA, _2X_SEL_Pin) == GPIO_PIN_RESET)
    {
        currMode = FAST_2X;
        xFactor = 2;
        All_Led_Off();
        Red_Led_On();
    }
    else if(HAL_GPIO_ReadPin(GPIOA, X_2_SEL_Pin) == GPIO_PIN_RESET)
    {
        currMode = SLOW_X_2;
        xFactor = 0.5;
        All_Led_Off();
        Blue_Led_On();
    }
    else
    {
        currMode = MEDIUM_X;
        xFactor = 1;
        All_Led_Off();
        Green_Led_On();
    }
}