ADS1148 無法讀取第一組之外的差動

ADS1148_WREG ( ADS_MUX0 , 0x01 ) ;

ADS1148_WREG ( ADS_VBIAS , 0x00 ) ;

ADS1148_WREG ( ADS_MUX1 , 0x28 ) ;

ADS1148_WREG ( ADS_IDAC0 , 0x06 ) ;

ADS1148_WREG ( ADS_IDAC1 , 0x0F ) ;

ADS1148_WREG ( ADS_SYS0 , 0x05 ) ;

此設定可以讀到 AIN0 & AIN1 的差動  

為何更改輸入源成 AIN4 & AIN5 , 卻無法讀到差動 

ADS1148_WREG ( ADS_MUX0 , 0x25 ) ;

ADS1148_WREG ( ADS_VBIAS , 0x00 ) ;

ADS1148_WREG ( ADS_MUX1 , 0x28 ) ;

ADS1148_WREG ( ADS_IDAC0 , 0x06 ) ;

ADS1148_WREG ( ADS_IDAC1 , 0xF4 ) ;

ADS1148_WREG ( ADS_SYS0 , 0x05 ) ;