有人用NXP的ARM7调试过TRF7960么?

我用LPC2138的SPI控制TRF7960,能写TRF7960的寄存器(通过写寄存器,SYS_CLK输出不同的频率可以验证),但读寄存器总是读不出来,读出来都是0,看SPISO的波形也总是低.TRF7960在读寄存器的时候需要切换CLK的极性.不知道哪位调试过这个,还请指教哪出了问题.下面是读寄存器的代码.
void
SpiReadSingle(u08_t *pbuf, u08_t number)
{   
//uint16 i;

SLAVE_SELECT_LOW;       // Start SPI Mode

while(number > 0)
{
  *pbuf = (0x40 | *pbuf);    // address, read, single
  *pbuf = (0x5f & *pbuf);    // register address

   SPI_SPDR =*pbuf;
   while(!(SPI_SPSR &0x80));
  
  SPI_SPCR = 0x30;//CPOL = 1, CPHA = 0
  
  SPI_SPDR =0;
  while(!(SPI_SPSR &0x80));
  *pbuf = SPI_SPDR;
  pbuf++;
  number--;

  SPI_SPCR = 0x20;//CPOL = 0, CPHA = 0
}

SLAVE_SELECT_HIGH;
}