求助！S3C2440的SPI驱动为什么读回来的数据都是0xff？

void SPI_InitialGPIO()

{

rGPECON |= 2<<22|2<<24|2<<26;//配置SPI0 GPE端口的GPE11 GPE12 GPE13 分别为MISO MOSI SPICLK

//rGPGCON |= 3<<4;//配置GPG端口的GPG2 为nss0

//rGPEUP &=~(0x3800);

rGPEUP |=(1<<11)|(1<<12)|(1<<13);//配置上拉

rGPGUP |=0x4;//GPG2上拉禁止

rGPGCON=rGPGCON & (~(3<<4)) | (1<<4);

rGPGDAT|=0x4;

rGPFCON = 0x1000;  

rGPFUP=0xb0;  

//rGPFDAT |= (6<<0);

//rGPBUP &= ~(1<<1);

}

//void SPI0_Interrupt_Init()

//{

//rINTMSK &=~(1<<22);

//pISR_SPI0 = (U32)SPI0_ISR;

//}

void SPI_Mode()

{

//        ClearPending(BIT_SPI0);//清除中断挂起

//配置寄存器

rSPPRE0=0x4;//SPICLK=5M

rSPCON0=(0<<5)|(1<<4)|(1<<3)|(1<<2)|(0<<1)|(0<<0);         //中断方式

//rSPPIN0=(0<<2)|(1<<1)|(0<<0);

//rGPGDAT &= 0XFFFB;

}  

unsigned char SPIReadByte(void)

{

unsigned char SpiRx;

//        ClearPending(BIT_SPI0);

rGPGDAT &= ~(1<<2);

while(！(rSPSTA0&0x1));

  SpiRx=rSPRDAT0;

while(！(rSPSTA0&0x1));

rGPGDAT |= (1<<2);

return SpiRx;       

}

void SPIWriteByte(unsigned char SPIData)

{

//ClearPending(BIT_SPI0);

rGPGDAT &= ~(1<<3);

while(！(rSPSTA0&0x1));

rSPTDAT0=SPIData;

while(！(rSPSTA0&0x1));

rGPGDAT |= (1<<3);       

}

我读取的数据也都是0xff，但是短接输入输出口的话，能正确接收数据，不知道问题出现在哪里

有知道的麻烦相互联系下！我qq526861258

小编问题解决了吗?