请问AD7710双通道输出一直为0XFFFFFF是为什么？

先读读别的寄存器看能读对不

读控制寄存器也是错误的，可是我看了感觉时序什么的都是对的
以下是我写控制寄存器的程序：
void WriteREG(unsigned long int puke)          //0x209022激活自校准模式   this sub function is to write 24bit data to register
{
  unsigned int flag = 0;
  unsigned int ShiftFlag = 0x0080;
  unsigned int High8 = 0, Low16 = 0, ShiftData = 0;
  int i = 0;
 
 
  High8 = (puke & 0x00FF0000)>>16;
  Low16 = puke & 0x0000FFFF;
 
   *P_IOA_Buffer = *P_IOA_Buffer & 0xFFFE; //set SCLK low
  *P_IOA_Buffer = *P_IOA_Buffer | 0x0010;     //set TFS high
  *P_IOA_Buffer = *P_IOA_Buffer | 0x0008;     //RFS taken high
  *P_IOA_Dir = *P_IOA_Dir | 0x0002;           //to configure SDATA as ouput
  *P_IOA_Attrib = *P_IOA_Attrib | 0x0002;
 
//start to write data to control register
  *P_IOA_Buffer = *P_IOA_Buffer & 0xFFDF;     // A0 set LOW,write control reg
 
  Delay1us();
 
  *P_IOA_Buffer = *P_IOA_Buffer & 0xFFEF;     // TFS set low
 
 
 
  for(i = 0; i<24; i++)
  { 
  if(0 == i)                           //deal with the high 8 bit
  {
  ShiftFlag = 0x0080;
  ShiftData = High8;
  }
  else if(8 == i)                         //deal with the low 16 bit
  {
  ShiftFlag = 0x8000;
  ShiftData = Low16;
  }
  flag = ShiftData & ShiftFlag;
 
 
  if(flag)
  {
  *P_IOA_Buffer = *P_IOA_Buffer | 0x0002;//SDATA=1  0010
// asm("INT OFF");
// Delay1us();
// asm("INT IRQ");
  *P_IOA_Buffer = *P_IOA_Buffer | 0x0001;//SLCK  a rising edge
// asm("INT OFF");
  Delay1us();
// asm("INT IRQ");
  *P_IOA_Buffer = *P_IOA_Buffer & 0xFFFE;//SLCK  a down  edge
  Delay1us();
  }
  else
  {
  *P_IOA_Buffer = *P_IOA_Buffer & 0xFFFD; //SDATA=0
// asm("INT OFF");
// Delay1us();
// asm("INT IRQ");
  *P_IOA_Buffer = *P_IOA_Buffer | 0x0001; //give SCLK a rising edge
// asm("INT OFF");
  Delay1us();
// asm("INT IRQ");
  *P_IOA_Buffer = *P_IOA_Buffer & 0xFFFE;
  Delay1us();
  }
  ShiftFlag = ShiftFlag >> 1;
  }
  *P_IOA_Buffer = *P_IOA_Buffer | 0x0010;   //set TFS high
  *P_IOA_Buffer = *P_IOA_Buffer | 0x0020;   //set A0 high
}

问一下，检查过IO的电平适配么
还有SPI的极性是否正确 么

检查了下，IO口配置好像有点问题，还在调，有进展跟您保持交流  ~很感谢