36.5.6 Selecting the Scanned Inputs

All available analog inputs can be configured for scanning. Class 2 and Class 3 inputs are sampled using the shared ADC module. A single conversion trigger source is selected for all of the inputs selected for scanning using the STRGSRC[4:0] bits (ADCCON1[20:16]). On each conversion trigger, the ADC module starts converting (in the natural priority) all inputs specified in the user-specified scan list (ADCCSS1). For Class 2 and Class 3 inputs, the trigger initiates a sequential sample/conversion process in the natural priority order.

An analog input belongs to the scan if it is:
  • A Class 3 input. For Class 3 inputs, scan is the only mechanism for conversion.
  • A Class 2 input that has the scan trigger selected as the trigger source by selecting the STRIG option in the TRGSRCx[4:0] bits located in the ADCTRG1 and ADCTRG2 registers

The trigger options available for scan are identical to those available for independent triggering of Class 2 inputs. Any Class 2 inputs that are part of the scan must have the STRIG option selected as their trigger source in the TRGSRCx[4:0] bits.

Note: The end-of-scan (EOS) is generated only if the last shared input conversion has completed. Until this condition is met, the scan sequence is still in effect. Therefore, the EOS Interrupt can be used for any scan sequence with any combination of input types.