Problem with USATT, cant receive anything from X-CTU

What IDE/Compiler?

Thanks for your replaying. I am using keil as my IDE.

For Keil, you want something like this to host the stdio on the target board.

#include <
stdio.h
>
/*----------------------------------------------------------------------------
Write character to Serial Port
*----------------------------------------------------------------------------*/
int ser_putchar (int c) {
while (!(USART1->SR & USART_FLAG_TXE));
USART1->DR = (c & 0x1FF);
return (c);
}
/*----------------------------------------------------------------------------
Read character from Serial Port (blocking read)
*----------------------------------------------------------------------------*/
int ser_getchar (void) {
while (!(USART1->SR & USART_FLAG_RXNE));
return ((int)(USART1->DR & 0x1FF));
}
#include <
rt_misc.h
>
#pragma import(__use_no_semihosting_swi)
struct __FILE { int handle; /* Add whatever you need here */ };
FILE __stdout;
FILE __stdin;
int fputc (int ch, FILE *f) { return (ser_putchar(ch)); }
int fgetc (FILE *f) { return (ser_getchar()); }
int ferror(FILE *f) {
/* Your implementation of ferror */
return EOF;
}
void _ttywrch(int ch) { ser_putchar(ch); }
void _sys_exit(int return_code) {
label: goto label; /* endless loop */
}