Resolved! USART3_IRQHandler is not invoked.
char recv_string[10];char data;int count = -1,i,data_check = -1;void USART3_IRQHandler(void) //my interrupt handler{ if(USART_GetITStatus(USART3,USART_IT_TXE)) { data = USART_GetChar(); if(data == 0x0D || data == 0x08) data_check = 1; e...