芯片的示例程序里面没有有关UART的配置，所以根据手册自己写了UART4配置（重映射PB0和PB1），实测下来没有数据输出，也没有进接收中断，能否看看是哪里配置有问题，具体配置如下：
void UART4_Init (uint32_t band)
{
USART_InitTypeDef USART_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO|RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE);
GPIO_PinRemapConfig( GPIO_FullRemap_USART4, ENABLE );
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
USART_InitStructure.USART_BaudRate = band;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init(UART4, &USART_InitStructure);
USART_ClearFlag(UART4, USART_FLAG_RXNE);
USART_ITConfig(UART4, USART_IT_RXNE, ENABLE);
USART_Cmd(UART4, ENABLE);
//NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1); //采用组别2
NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init( &NVIC_InitStructure );
}
void UART4_IRQHandler(void)
{
if(USART_GetITStatus(UART4, USART_IT_RXNE) != RESET) //若接收数据寄存器满
{
printf("%d\r\n", USART_ReceiveData(UART4));
}
// printf("INT\r\n");
USART_ClearITPendingBit(UART4,USART_IT_ORE);
}
