Problem with UART on Bluepill (F103C8T6) - no communication | Std Peripheral Library

[AJova.1]

I've a problem with UART on Bluepill (STM32F103C8T6). Let's say that I need to send some string via UART periodically using Std Peripheral Library . Below I post simple code which 'propably' should work. What I know for sure is that devices (bluepill and usb-uart converter) work fine (I've written similiar code but using HAL library and it worked in the same setting). Maybe the case is Clock Configuration? Thank You for any help...

#include "stm32f10x.h"
 
void USART_PutChar(char c)
{
    while (!USART_GetFlagStatus(USART2, USART_FLAG_TXE));
    USART_SendData(USART2, c);
}
 
void USART_PutString(char *s)
{
    while (*s)
    {
         USART_PutChar(*s++);
    }
}
 
 
int main(void)
{
	GPIO_InitTypeDef GPIOInit;
    USART_InitTypeDef USART_InitStruct;
 
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
 
    //LED
    GPIO_InitTypeDef GPIO_InitDef;
    GPIO_InitDef.GPIO_Pin = GPIO_Pin_13;
    GPIO_InitDef.GPIO_Mode = GPIO_Mode_Out_OD;
    GPIO_InitDef.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOC, &GPIO_InitDef);
 
    //PA2 Tx
    GPIO_StructInit(&GPIOInit);
    GPIOInit.GPIO_Pin = GPIO_Pin_2;
    GPIOInit.GPIO_Speed = GPIO_Speed_50MHz;
    GPIOInit.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(GPIOA, &GPIOInit);
 
    //PA3 Rx
    GPIOInit.GPIO_Pin = GPIO_Pin_3;
    GPIOInit.GPIO_Speed = GPIO_Speed_50MHz;
    GPIOInit.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIOInit);
 
    // USART2
    USART_InitStruct.USART_WordLength = USART_WordLength_8b;
    USART_InitStruct.USART_StopBits = USART_StopBits_1;
    USART_InitStruct.USART_Parity = USART_Parity_No;
    USART_InitStruct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_InitStruct.USART_BaudRate = 9600;
    USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_Init(USART2, &USART_InitStruct);
    USART_Cmd(USART2, ENABLE);
 
    while (1)
    {
    	USART_PutString("Test\n");
    }
}