void Tim3_init(void)// 24 MHz clock, 200 Hz int
    {
        RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
        TIM3->PSC = 1200 - 1; //Prescaler
        TIM3->CCMR1|=TIM_CCMR1_OC1PE|TIM_CCMR1_OC2PE;// Preload (shadow) registers for CCR1, CCR2 - compare registers (analog OCRA, OCRB)
        TIM3->CCER|=TIM_CCER_CC1E|TIM_CCER_CC2E;// Signal is output on the corresponding output pin.
        TIM3->CCER|=TIM_CCER_CC1P;// Chan 1 active low.
        TIM3->ARR = 100; // Auto reload value - val, when timer reloads to 0!!.
        TIM3->CR2|=TIM_CR2_MMS_1;// For ADC start point on timer refresh
        TIM3->CR1 |= TIM_CR1_CEN; // Enable clock
    }
    
    int main(void)
    {
        Tim3_init();// PWM Timer
        TIM3->CCR1=30;// Compare register 1 0-100 %
        TIM3->CCMR1|=TIM_CCMR1_OC1M_2|TIM_CCMR1_OC1M_1;// PWM mode 1
        while(1);
    }