51.6.8 Comparison Window

The AFEC features automatic comparison functions. It compares converted values to a low threshold, a high threshold or both, depending on the value of AFEC_EMR.CMPMODE. The comparison can be done on all channels or only on the channel specified in AFEC_EMR.CMPSEL. To compare all channels, AFEC_EMR.CMPALL must be set.

Moreover, a filtering option can be set by writing the number of consecutive comparison errors needed to raise the flag. This number can be written and read in AFEC_EMR.CMPFILTER.

The flag can be read on AFEC_ISR.COMPE and can trigger an interrupt.

The high threshold and the low threshold can be read/written in the Compare Window Register (AFEC_CWR).

Depending on the sign of the conversion, chosen by setting the SIGNMODE bit in the AFEC Extended Mode Register, the high threshold and low threshold values must be signed or unsigned to maintain consistency during the comparison. If the conversion is signed, both thresholds must also be signed; if the conversion is unsigned, both thresholds must be unsigned. If comparison occurs on all channels, the SIGNMODE bit must be set to ALL_UNSIGNED or ALL_SIGNED and thresholds must be set accordingly.