5.2.5.10.1 Input-Output Transfer Functions

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

• Single-ended—ADC_CCR.DIFFx = 0. This is the default mode after a reset.
• Differential—ADC_CCR.DIFFx = 1 (see the figure Analog Full Scale Ranges in Single-ended/Differential Applications). In Differential mode, the ADC requires differential input signals with a VDD/2 common mode voltage (refer to the section “Electrical Characteristics”).

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

In the formulae below, REFP = ADVREFP, REFN = GNDIN33.

Single-ended mode:

Differential mode:

If ADC_MR.ANACH is set, the parameters defined in ADC_CCR are applied to all channels.

The following table gives the internal positive and negative ADC inputs assignment with respect to the programmed mode (ADC_CCR.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.