Datasheet

273
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 16-3. No Separated Backup Supply Powering Scheme
Note: Restrictions: With Main Supply < 3V, some peripherals such as USB and ADC might not be operational. Refer to the
DC Characteristics of the product for actual possible ranges for such peripherals.
16.4.5 Supply Monitor
The Supply Controller embeds a supply monitor which is located in the VDDBU Backup Power Supply and which
monitors VDDUTMI power supply.
The supply monitor can be used to prevent the processor from falling into an unpredictable state if the Main power
supply drops below a certain level.
The threshold of the supply monitor is programmable. It can be selected from 1.9V to 3.4V by steps of 100 mV.
This threshold is programmed in the SMTH field of the Supply Controller Supply Monitor Mode Register
(SUPC_SMMR).
The supply monitor can also be enabled during one slow clock period on every one of either 32, 256 or 2048 slow
clock periods, according to the choice of the user. This can be configured by programming the SMSMPL field in
SUPC_SMMR.
Enabling the supply monitor for such reduced times allows to divide the typical supply monitor power consumption
respectively by factors of 32, 256 or 2048, if the user does not need a continuous monitoring of the VDDUTMI
power supply.
A supply monitor detection can either generate a reset of the core power supply or a wake up of the core power
supply. Generating a core reset when a supply monitor detection occurs is enabled by writing the SMRSTEN bit to
1 in SUPC_SMMR.
VDDBU
VDDIN
Voltage
Regulator
VDDOUT
Main Supply (1.8V-3.6V)
VDDCORE
VDDIO
VDDANA
VDDUTMI
VDDPLL