3.11.2.2 DVCC Supply Voltage Regulator
The DVCC supply voltage is enabled by a power-on. This happens when the PWRON pin (port PB4, as shown in the Figure 3-98) is set to high or an NPWRONx pin (Ports PC1 to PC5 and PB7) is set to low for a time period longer than Tpower_on_REQ. This time is needed to allow detection of the wake-up pin. The customer application software or an external microcontroller can verify the validity of a power-up by reading the corresponding event flags provided by the ATA8510/15 firmware. An external 22-nF blocking capacitor ensures the stability of the internal DVCC supply voltage regulator circuit. Values other than 22 nF must not be used for this capacitor.
The DVCC supply voltage can be turned off by setting the SUPCR.DVDIS register bit if no NPWRONx or PWRON pin is active or by using the OFF command.