AD7792测温测出来的值一直为0

用AD7792测四线制铂电阻，但是测出来的值一直为0，有没有哪位大佬帮忙看看哪里有问题，谢谢
Resettime=32;
CLK_H;
CS_L;
MOSI_H;
while(ResetTime--)  //超过连续32个周期为高电平即复位
{
  CLK_L;
  delay_us(200);
  CLK_H;
  delay_us(200);

}
delay_us(500);
    AD7792WriteByte(WriteConfReg);  //configuration register
    AD7792WriteByte(0x12);//单极性，增益Gain 4
    AD7792WriteByte(0x90);//internal Reference，带缓冲
   
    while(1)
    {  
        AD7792WriteByte(WriteIOReg);//IO register
        AD7792WriteByte(0x03);
        AD7792WriteByte(WriteModeReg);//Mode Register
        AD7792WriteByte(0x20);//单次转换
        AD7792WriteByte(0x0A);//inter 64 kHZ clock.internal clock is not available at the clk pin.
        AD7792WriteByte(ReadStateReg);//write to Communication register.The next step is to read from Status register.
        status = AD7792Read(8);
        while((status&0x80) == 0x80)  //wait for the end of convertion by polling the status register RDY bit
        {
            AD7792WriteByte(ReadStateReg);//write to Communication register.The next step is to read from Status register.
            status = AD7792Read(8);
            UARTprintf("status:%xn", status);
        }
        AD7792WriteByte(ReadDataReg); //write to Communication register.The next step is to read from Data register.
        AD7792_Data = AD7792Read(16);
        UARTprintf("V:%dn", AD7792_Data);