Functional Description
201
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
System Control
4.1.2.8
Hibernation Module Reset
When the Hibernation module has been configured and powered by an initial cold POR and is
subsequently put into hibernation mode, a wake event (not including an external reset pin wake) causes
the module to generate a system reset. This reset signal resets all circuitry on the device with the
exception of the Hibernation module. All registers of the Hibernation module retain their values after this
reset.
When the Hibernation module receives a wake event and V
DD
is enabled, a system reset sequence
occurs:
1. The POR or EXT bit in the RESC register is set.
2. An internal reset is asserted.
3. The internal reset is released and the microcontroller loads from memory the initial stack pointer, the
initial program counter, and the first instruction designated by the program counter.
4. Execution begins.
5. The HIBRIS register in the Hibernation module can be read to determine the cause of the reset.
6. The POR or EXT bit in the RESC register is cleared by writing 0.
4.1.2.9
HSSR Reset
The Hardware System Service Request (HSSR) register can be used to restore the device back to factory
settings. A successful write to the HSSR register initiates a system reset. The reset initialization process
executes before examining the HSSR register and processing the command. The HSSR register can be
accessed only in privileged mode.
Before the return-to-factory settings routine has completed, a system reset sequence executes and the
HSSR bit in the RESC register is set. After the HSSR function has been processed, the CDOFF field in
the HSSR register is written with the outcome of the function processing and another HSSR system reset
is executed. The HSSR bit can be cleared in the RESC register by writing 0.
For more information regarding use of the HSSR register, see
.
4.1.3 Nonmaskable Interrupt
The microcontroller has multiple sources of nonmaskable interrupt (NMI):
•
The assertion of the NMI signal.
•
A main oscillator verification error.
•
The NMISET bit in the Interrupt Control and State (INTCTRL) register in the Cortex-M4F (see
).
•
The Watchdog module time-out interrupt when the INTTYPE bit in the WDTCTL register is set (see
•
Tamper event (see
for more information).
•
Any of the following BOR trigger events:
–
V
DDA
under BOR setting
–
V
DD
under BOR setting
Software must read the cause of the interrupt in the NMI Cause (NMIC) register to determine the source.
4.1.3.1
NMI Pin
The NMI signal is an alternate function for the GPIO port pins specified in the device-specific data sheet.
The alternate function must be enabled in the GPIO for the signal to be used as an interrupt, as described
in
. Enabling the NMI alternate function requires the use of the GPIO lock and commit function,
similar to the requirements of the GPIO port pins associated with JTAG/SWD functionality (see
). The active sense of the NMI signal is high; asserting the enabled NMI signal above V
IH
initiates the NMI interrupt sequence.