void spi_slave_init()
{
     //NSS
     GPIOA->DDR &= ~SPI_SSEL_PIN; //输入模式
    GPIOA->CR1 &= ~SPI_SSEL_PIN; //浮空输入
    GPIOA->ODR &= (uint8_t)~SPI_SSEL_PIN; //write low

     GPIOC->DDR |= SPI_MISO_PIN; //输出模式
    GPIOC->CR1 |= SPI_MISO_PIN; //推挽输出
   
     GPIOC->DDR &= ~SPI_MOSI_PIN; //输入模式
    GPIOC->CR1 &= ~SPI_MOSI_PIN; //浮空输入
   
     GPIOC->DDR &= ~SPI_CLK_PIN;  //输入模式
    GPIOC->CR1 &= ~SPI_CLK_PIN;  //浮空输入
   
         SPI_DeInit();        
         // Initialize SPI in Slave mode, NSS hardwere management  */
         SPI_Init(SPI_FIRSTBIT_MSB, SPI_BAUDRATEPRESCALER_2, SPI_MODE_SLAVE, SPI_CLOCKPOLARITY_HIGH,
                 SPI_CLOCKPHASE_2EDGE, SPI_DATADIRECTION_2LINES_FULLDUPLEX, SPI_NSS_SOFT,(uint8_t)0x07);
         SPI_ITConfig(SPI_IT_RXNE, ENABLE);// Receive buffer not empty interrupt Enable
         SPI_Cmd(ENABLE); // SPI enable
}

uint8_t spi_rw(uint8_t byte)
{
     char ch = 0;
     
     while (SPI_GetFlagStatus(SPI_FLAG_TXE) == RESET);
     SPI->DR = byte;

     while(SPI_GetFlagStatus(SPI_FLAG_RXNE) == RESET);
     ch = ((uint8_t)SPI->DR);
     
     return ch;
}

INTERRUPT_HANDLER(SPI_IRQHandler, 10)
{
   /* In order to detect unexpected events during development,
      it is recommended to set a breakpoint on the following instruction.
   */
   uint8_t Rx_byte;
   Rx_byte = spi_rw(0x18);
   printf("%x ", Rx_byte);
}
中断里面收到的打印全是0x1，不知道什么原因啊，但是SPI Master可以收到stm8发送的0x18