u8 NRF24L01_Read_Buf(u8 reg,u8 *pBuf,u8 len)
{
  u8 status,u8_ctr;               
  NRF24L01_CSN = 0;           //ê1ÄüSPI′«êä
  status=SPI1_ReadWriteByte(reg);//·￠Ëí¼Ä′æÆ÷Öμ(λÖÃ),2￠¶áè¡×′ì¬Öμ             
  for(u8_ctr=0;u8_ctr<len;u8_ctr++)pBuf[u8_ctr]=SPI1_ReadWriteByte(0XFF);//&#182;á3&#246;êy&#190;Y
  NRF24L01_CSN=1;       //1&#216;±&#213;SPI′&#171;ê&#228;
  return status;        //·μ&#187;&#216;&#182;áμ&#189;μ&#196;×′ì&#172;&#214;μ
}


  有人知道这的for(u8_ctr=0;u8_ctr<len;u8_ctr++)pBuf[u8_ctr]=SPI1_ReadWriteByte(0XFF);中写入0xFF是为什么吗？