求助SD16_A选择参考电压

你好，参照例程具体的设置如下

  SD16CTL = SD16REFON + SD16SSEL_1;         // 参考电压选择1.2V ref,ADC的时钟源选择 SMCLK
  SD16INCTL0 = SD16INCH_1;                               // A1+/-
  SD16CCTL0 =  SD16UNI + SD16IE;                    // 256OSR, unipolar, interrupt enable
  SD16AE = SD16AE2;                                                // P1.1 A1+,        A1- = VSS
  SD16CCTL0 |= SD16SC;                                        // Set bit to start conversion

XinXin Li，

对于SD16而言，其电压参考源可以直接使用内部参考源1.2V，只要将SD16REFON设为1即可， 不需要输出的。另外使用它时，建议在VREF和AVSS间加一个100nf的电容。当然，如果想要将其输出，需要设置SD16VMIDON = 1。此时建议在VREF和AVSS间加一个470nf的电容。也是可以的在User guide上有详细的描述，如下所示：

26.2.3 Voltage Reference Generator
The SD16_A module has a built-in 1.2-V reference. It is enabled by the SD16REFON bit. When using the
internal reference an external 100-nF capacitor connected from VREF to AVSS is recommended to reduce
noise. The internal reference voltage can be used off-chip when SD16VMIDON = 1. The buffered output
can provide up to 1 mA of drive. When using the internal reference off-chip, a 470-nF capacitor connected
from VREF to AVSS is required. See the device-specific data sheet for parameters.
An external voltage reference can be applied to the VREF input when SD16REFON and SD16VMIDON are
both reset.

您好，我想问一下，对于MSP430F478的的SD16_A，外部参考Vref可否直接接到Vcc（3.3V），如果可以的话，它的可检测的输入电压信号范围是多少？0~3.3V还是0~1.65V呢？如果我要检测的信号是5V，那么需要如何处理呢？谢谢~~