To use the
RST
pin as a wake source, the
WURSTEN
bit must be set in the
Hibernate I/O
Configuration (HIBIO)
register and the
WUUNLK
bit must be set in the same register.
To enable any of the assigned GPIO pins as a wake source, the
WUUNLK
bit must be set in the
HIBIO
register and the wake configuration must be programmed through the
GPIOWAKEPEN
and
GPIOWAKELVL
registers in the GPIO module. Please refer to “General-Purpose Input/Outputs
(GPIOs)” on page 742 for more information on programming the GPIOs.
Note:
The
RST
pin and GPIO wake sources are cleared by a write to either or both the
RSTWK
and
PADIOWK
bits. This clears the source of interrupts for
RSTWK
,
PADIOWK
and the
GPIOWAKESTAT
register.
TMPR[3:0]
are enabled by setting the appropriate
ENn
bits the
Tamper IO Control and Status
(HIBTPIO)
register. The
HIBTPIO
register overrides the GPIO port configuration registers. By setting
the
WAKE
bit in the
Tamper Control (HIBTPCTL)
register, a tamper event can cause a wake from
Hibernate. If a tamper event occurs, the time of the event and the status of the tamper pins are
logged in the
Tamper Log (HIBTPLOG)
register.
By setting the
RTCWEN
bit in the
HIBCTL
register a wake from hibernate can occur when the value
of the
HIBRTCC
register matches the value of the
HIBRTCM0
register and the value of the
RTCSSC
field matches the
RTCSSM
field in the
HIBRTCSS
register.
To allow a wake from Hibernate on a low battery event, the
BATWKEN
bit in the
HIBCTL
register
must be set. In this configuration, the battery voltage is checked every 512 seconds while in
hibernation. If the voltage is below the level specified by the
VBATSEL
field, the
LOWBAT
interrupt
is set in the
HIBRIS
register.
Upon external wake-up, external reset, tamper event, or RTC match, the Hibernation module delays
coming out of hibernation until V
DD
is above the minimum specified voltage, see Table
When the Hibernation module wakes, the microcontroller performs a normal power-on reset. The
normal power-on reset does not reset the Hibernation module or Tamper module, but does reset
the rest of the microcontroller. Software can detect that the power-on was due to a wake from
hibernation by examining the raw interrupt status register (see “Interrupts and Status” on page 548)
and by looking for state data in the battery-backed memory (see “Battery-Backed
Memory” on page 545).
7.3.12
Arbitrary Power Removal
The microcontroller goes into hibernation if V
DD
is arbitrarily removed when the
CLK32EN
bit is set
and any of the following bits are set:
■
TPEN
bit in the
HIBTPCTL
register
■
PINWEN
bit in the
HIBCTL
register
■
RTCEN
bit in the
HIBCTL
register
The microcontroller wakes from hibernation when power is reapplied.
If the
CLK32EN
bit is set but the
TPEN
,
PINWEN
, and
RTCEN
bits are all clear, the microcontroller
still goes into hibernation if power is removed; however, when V
DD
is reapplied, the MCU executes
a cold POR and the Hibernation module is reset. If the
CLK32EN
bit is not set and V
DD
is arbitrarily
removed, the part is simply powered off and executes a cold POR when power is reapplied.
547
June 18, 2014
Texas Instruments-Production Data
Tiva
™
TM4C1294NCPDT Microcontroller