led+串口 重定向 STM32F030F4P6
重定向报错 axf: Error: L6200E: Symbol fgetc multiply defined (by usart.o and main.o).

把

    #include "stdio.h"
int fputc(int ch, FILE *fp)
{HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xffff);return ch;
}int fgetc(FILE *fp)
{uint8_t ch = 0;HAL_UART_Receive(&huart1, &ch, 1, 0xffff);return ch;
}

放在main.c 开头/* USER CODE BEGIN PV */就可以了