34.4 OPA Operation with ADC

The OPA module provides internal connections directly to the ADC, allowing it to be used for analog signal conditioning before a signal is converted by the ADC. In this mode of operation, the output of the OPA (OPAxOUT) will connect internally to the input of the ADC, and any ADC conversions will be performed on that signal. When using this mode of operation, the ADPCH register of the ADC module may be used to select one of the available noninverting OPA input pins (OPAxIN+) Both the ADC and the OPA module must be configured accordingly to use this mode of operation.

Tip:
  1. When using the OPA module with the ADC in this mode of operation, the OPA input pin selection determined using the ADC input channel selection registers will take precedence over the input pin selection using the PSS and NSS bits.
  2. Although the output of the OPA (OPAxOUT) is connected internally to the ADC in this mode of operation, the OPAxOUT pin cannot be used as a general purpose I/O at this time.