Printf redirection of serial port under sw4stm32 (SW4)

keil(mdk)

sw4stm32（SW4） 

int __io_putchar(int ch)//for sw4
{
	// Block send a byte （ Wait until the last one is sent , Or wait until the current byte is sent ）
	// return ch
	USART_SendData(USART1, (unsigned char) ch);
	while (!(USART1->SR & USART_FLAG_TXE));
	return (ch);
}
int fputc(int ch, FILE *f)//for mdk
{
	USART_SendData(USART1, (unsigned char) ch);
	while (!(USART1->SR & USART_FLAG_TXE));
	return (ch);
}

Reprinted address ：https://blog.csdn.net/shentianguo1985/article/details/84561477