ADS1248 读出来数据都是0

目前寄存器能读能写，但是读取数据，一直读出来为0，求解

Set_ADS1247_Chip_Enable(1);
Send_Data_SPI(WRITE_MUX0_REGISTER);
Send_Data_SPI(0x0e); //写入15个
Send_Data_SPI(0x2e); //MUX0 00101110
Send_Data_SPI(0);//VBIAS
Send_Data_SPI(0x20);//MUX1 00100000 00110000
Send_Data_SPI(0x0f);//SYS0 00001111
Send_Data_SPI(0);//OFC0
Send_Data_SPI(0);//OFC1
Send_Data_SPI(0);//OFC2
Send_Data_SPI(0);//FSC0
Send_Data_SPI(0);//FSC1
Send_Data_SPI(0);//FSC2
Send_Data_SPI(0X0e);//IDAC0 00001110
Send_Data_SPI(((uint8_t)IDAC1_AIN4 + (uint8_t)IDAC2_AIN7)); //IDAC1 0x47
Send_Data_SPI(0);//GPIOCFG 0
Send_Data_SPI(0xff);//GPIODIR ff
Send_Data_SPI(0);//GPIODAT 00
Clear_ADS1247_Chip_Enable(1);

while(1)
{

Set_ADS1247_Chip_Enable(1);
while(DOUT1);
Send_Data_SPI(0x12);
DIN_ADS_1 ;
tab[0] = Receive_Data_SPI(1);
tab[1] = Receive_Data_SPI(1);
tab[2] = Receive_Data_SPI(1);
Receive_Data_SPI(1);
Clear_ADS1247_Chip_Enable(1);