SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 277

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

17.4.4
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
Using Backup Batteries/Backup Supply
The product can be used with or without backup batteries, or more generally a backup supply.
When a backup supply is used (See
mode and no other external supply is applied on the chip. In this case the user needs to clear
VDDIORDY bit in the Supply Controller Mode Register (SUPC_MR) at least two slow clock peri-
ods before VDDIO voltage is removed. When waking up from Backup mode, the programmer
needs to set VDDIORDY.
Figure 17-2. Separated Backup Supply Powering Scheme
Note:
When a separated backup supply for VDDBU is not used (See
voltage applied on VDDIO is kept, all of the I/O configurations (i.e. WKUP pin configuration) are
kept during backup mode. When not using backup batteries, VDDIORDY is set so the user does
not need to program it.
Restrictions: With Main Supply < 3V, some peripherals such as USB and ADC might not be oper-
ational. Refer to the DC Characteristics of the product for actual possible ranges for such
peripherals.
Main Supply (1.8V-3.6V)
Figure
Backup Batteries
17-2), only VDDBU voltage is present in Backup
VDDUTMI
VDDANA
VDDCORE
VDDBU
VDDIO
FWUP
VDDIN
VDDPLL
VDDOUT
SHDN
Figure
17-3), since the external
Regulator
Voltage
SAM3X/A
SAM3X/A
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