Data Sheet

123
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
There are two groups of reset sources:
z Power Reset: Resets caused by an electrical issue.
z User Reset: Resets caused by the application.
The table below lists the parts of the device that are reset, depending on the reset type.
The external reset is generated when pulling the RESET
pin low. This pin has an internal pull-up, and does not need to
be driven externally during normal operation.
The POR, BOD12 and BOD33 reset sources are generated by their corresponding module in the System Controller
Interface (SYSCTRL).
The WDT reset is generated by the Watchdog Timer.
The System Reset Request (SysResetReq) is a software reset generated by the CPU when asserting the
SYSRESETREQ bit located in the Reset Control register of the CPU (See the ARM
®
Cortex
®
Technical Reference
Manual on http://www.arm.com).
Table 15-2. Effects of the Different Reset Events
Power Reset User Reset
POR, BOD12, BOD33 External Reset
WDT Reset,
SysResetReq
RTC
All the 32kHz sources
WDT with ALWAYSON feature
Generic Clock with WRTLOCK
feature
Y N N
Debug logic Y Y N
Others Y Y Y