28.4 Charge Pump Threshold
The Charge Pump Threshold (CPT) bit indicates whether or not VDD is at an
            acceptable operating level. Charge pump hardware compares VDD to the
            threshold voltage (VAUTO), which is set at 4.096V. If VDD is above
                VAUTO, the CPT bit is set (CPT = 1). If VDD
            is below VAUTO, CPT is clear (CPT = 0).
