Stm32 Time Base Interrupt (without any library)

I use Stm32f103c8t6 processor and I want to make 1 second counter. Normaly I dont use tımer update ınterrupt and my counter counts correctly but when I add timer update ınterrupt in code my counter doesnt count correctly. So fast increment. And ı cant remove update interrupt flag (UIF) in TIM1's SR register. If I remove this flag my code is entering infinty loop. I cant any solution for this problem. Thanks for help

This part is bring in startup_stm32f10x_md.s

/**
 * @brief  This is the code that gets called when the processor receives an
 *         unexpected interrupt.  This simply enters an infinite loop, preserving
 *         the system state for examination by a debugger.
 *
 * @param  None
 * @retval : None
*/
    .section    .text.Default_Handler,"ax",%progbits
Default_Handler:
Infinite_Loop:
    b   Infinite_Loop -----------------------------> my code is stuck here
    .size   Default_Handler, .-Default_Handler

And this is a my code.

#include <stddef.h>
#include "stm32f10x.h"

void CLK_Config(){
     RCC-> CR = 0x00000000;             //CR Reset
     RCC-> CR |= 0x00010000;            //HSE enable
     while(!(RCC-> CR & 0x00020000));   //HSE FLAG control
     RCC-> CR |= 0x00080000;            //CSS enable
     RCC-> CR |= 0x01000000;            //PLL On
     RCC-> CFGR |= 0x00010000;          //HSE Select PLL input
     RCC-> CFGR |= 0x001C0000;          //PLL Multi With 9 = 72 Mhz
     RCC-> CFGR |= 0x00000002;          //PLL Select as SYSCLK
     RCC-> CFGR |= 0x00000400;          //APB1 Clock divided by 2

     RCC-> APB1ENR |= 0x18000000;       //APB1 BKP Clock Enable
     PWR-> CR |= 0x0100;                //PWR BKP Access Enable

     RCC-> APB2ENR |= 0x00000001;       //APB2 AFIO Clock Enable
}

void TIM1_Config(){
     RCC-> APB2ENR  |= 0x00000800;      //TIM1 CLK Enable
     TIM1-> CR1     |= 0x0085;          //Update Request Source, Counter Enable
     TIM1-> DIER     = 0x0001;          //Update Interrupt Enable
     TIM1-> ARR      = 0x1F40;          //8000 is set as Auto Reload Value
     TIM1-> PSC      = 0x2327;          //9000 is set as Prescaler Value for 1 sn Formula: 1sn=1Hz=(PCLK/(PSC*ARR))
}

void USART1_Config(){
    RCC-> APB2ENR   |= 0x00000004;      //GPIOA CLK Enable
    GPIOA-> CRH     |= 0x00000AA0;      //GPIOA 10,9 Push-Pull Alternate Function 2Mhz
    RCC-> APB2ENR   |= 0x00004000;      //USART1 CLK Enable
    USART1-> BRR    |= 0x00001D4C;      //USART1 Baund Rate 9600
    USART1-> CR1    |= 0x000020C8;      //USART, TXE Interrupt, TC Interrupt, Transmitter Enable
}

void Interrupt_Config(){
    NVIC-> ISER[0]  |= 0x02000000;      //NVIC TIM1 UP
    NVIC-> ISER[1]  |= 0x00000020;      //NVIC USART1 Global Interrupt

    NVIC-> IP[25]   = 0x10;             //TIM1 UP Interrupt Priority 2.         25th Interrupt
    NVIC-> IP[37]   = 0x40;             //USART1 Global Interrupt Priority 5.   37th Interrupt

}

uint8_t count1sec; // Global variable

int main(void)
{
    CLK_Config();
    Interrupt_Config();
    TIM1_Config();
    USART1_Config();

  while (1)
  {
      if(count1sec != 0){
          USART1-> DR = count1sec;
      }
  }

}

void TIM1_UP_IRQHandler(){
    TIM1-> SR = 0x00000000;
    NVIC-> ICPR[0] = 0x02000000;
    count1sec += 1;
}

I'm not able to detect the exact cause of your problem, but I can provide some suggestions and make some guesses.

1) Do not use magic numbers! Use predefined bit names. Here is an example:

USART2->BRR = 0x1a0; // 115200 bps @ 24 MHz (OVER8=1, ONEBIT=1)
USART2->CR1 |= USART_CR1_OVER8 // Oversampling is reduced for higher baud rates
            | USART_CR1_IDLEIE // Idle line detection interrupt is enabled
            | USART_CR1_TE // Transmitter is enabled
            | USART_CR1_RE; // Receiver is enabled
USART2->CR3 |= USART_CR3_ONEBIT // One bit mode for increased clock deviation tolerance
            | USART_CR3_DMAT // DMA for TX
            | USART_CR3_DMAR; // DMA for RX
USART2->CR1 |= USART_CR1_UE; // Enable USART2

2) Use CMSIS functions to access NVIC functionality. Here is an example:

NVIC_SetPriority(TIM6_DAC_IRQn, 2);
NVIC_EnableIRQ(TIM6_DAC_IRQn);

3) You have Auto-reload preload enable bit set in TIM1->CR1 register. This normally delays the update of the ARR register until the next update event. I'm not sure how it works during the initial run of the timer, but I suggest to avoid using it until you're sure everything works fine.

4) You normally don't need to clear pending bits in NVIC. I suggest removing that code from the ISR. Clearing the flags in the peripheral registers is all you need and you're already doing it with TIM1->SR = 0 line.

5) The reason you stuck in Infinite_Loop is probably the USART TX interrupt. It gets fired but as you didn't supply a ISR for it, it falls into the Default_Handler. You load DR manually in the main loop, so in this case you don't even need USART TX interrupts.