Output of edge counter/compare selected as source. Note that when this bitfield is set to 1, the internal edge counter is enabled and the rising and/or falling edges specified by the CAPTCTRLB[EDGB0] and CAPTCTRLB[EDGB1] fields are ignored. The software must still place a value other than 00 in either or both of the CAPTCTLRB[EDGB0] and/or CAPTCTRLB[EDGB1] fields in order to enable one or both of the capture registers.