LP-CC2652RB: ADC 配置

junde deng

Part Number: LP-CC2652RB
Other Parts Discussed in Thread: CC2652RB

Hi Ti:

我在配置 ADC 的过程有如下疑问，请多多指教：

1. reference source 选 Fixed / VDDS 哪个精度更高呢？ Fixed 的参考电压是多少呢？采样电压范围是多少呢？

2. Input Scaling 这个参数是什么意思呢？我看到其他 ADC 设置中有 Gain 这个参数，是类似的意思吗？

3. Adjust Sample Value 这里的调整是怎么调整呀？

多谢！

0 Kevin Qiu 4 年多前

1，2.如果VDDS是恒压源，那二者精度是差不多的

junde deng 说：
我看到其他 ADC 设置中有 Gain 这个参数，是类似的意思吗？

是的，具体参考下面的说明

In practice, using the internal fixed voltage reference sets the upper range of the ADC to a fixed value. That value is 4.3V with input scaling enabled and ~1.4785V with input scaling disabled. In this mode, the output is a function of the input voltage multiplied by the resolution in alternatives (not bits) divided by the upper voltage range of the ADC. Output = Input (V) * 2^12 / (ADC range (V))
Using VDDS as a reference scales the upper range of the ADC with the battery voltage. As the battery depletes and its voltage drops, so does the range of the ADC. This is helpful when measuring signals that are generated relative to the battery voltage. In this mode, the output is a function of the input voltage multiplied by the resolution in alternatives (not bits) divided by VDDS multiplied by a scaling factor derived from the input scaling. Output = Input (V) * 2^12 / (VDDS (V) * Scaling factor), where the scaling factor is ~1.4785/4.3 for input scaling disabled and 1 for input scaling enabled.

注意ADC输入电压不能超过VDDS

3.一般不用这个,CC2652RB采样值基本上是很准确的