66.6.10.1 Input-output Transfer Functions

The ADC can be configured to operate in the following input voltage modes:

• Single-ended—ADC_COR.DIFFx = 0. This is the default mode after a reset.
• Differential—ADC_COR.DIFFx = 1 (see the figure below). In Differential mode, the ADC requires differential input signals having a VDD/2 common mode voltage (refer to section “Electrical Characteristics”).

The following equations give the unsigned ADC input-output transfer function in each mode⁽¹⁾. With signed conversions (see field ADC_EMR.SIGNMODE), subtract 2047 from the ADC_LCDR.DATA value given below.

In the formula, REFP = VREFP, REFN = VREFN.

Single-ended mode:

Differential mode:

If ADC_MR.ANACH is set, the ADC can manage both differential channels and single-ended channels. If ADC_MR.ANACH is cleared, the parameters defined in ADC_COR are applied to all channels.

The following table give s the internal positive and negative ADC inputs assignment with respect to the programmed mode (ADC_COR.DIFFx).

For example, if Differential mode is required on channel 0, input pins AD0 and AD1 are used. In this case, only channel 0 must be enabled by writing a 1 to ADC_CHER.CH0.