LM3S5G31 Datasheet, PDF (56/1223 Pages) Texas Instruments – Stellaris LM3S5G31 Microcontroller

Architectural Overview
1.3.5.5
1.3.5.6
Hibernation Module (see page 286)
The Hibernation module provides logic to switch power off to the main processor and peripherals
and to wake on external or time-based events. The Hibernation module includes power-sequencing
logic and has the following features:
■ 32-bit real-time counter (RTC)
– Two 32-bit RTC match registers for timed wake-up and interrupt generation
– RTC predivider trim for making fine adjustments to the clock rate
■ Two mechanisms for power control
– System power control using discrete external regulator
– On-chip power control using internal switches under register control
■ Dedicated pin for waking using an external signal
■ RTC operational and hibernation memory valid as long as V_BAT is valid
■ Low-battery detection, signaling, and interrupt generation
■ Clock source from a 32.768-kHz external oscillator or a 4.194304-MHz crystal; 32.768-kHz
external oscillator can be used for main controller clock
■ 64 32-bit words of battery-backed memory to save state during hibernation
■ Programmable interrupts for RTC match, external wake, and low battery events
Watchdog Timers (see page 596)
A watchdog timer is used to regain control when a system has failed due to a software error or to
the failure of an external device to respond in the expected way. The Stellaris Watchdog Timer can
generate an interrupt or a reset when a time-out value is reached. In addition, the Watchdog Timer
is ARM FiRM-compliant and can be configured to generate an interrupt to the microcontroller on its
first time-out, and to generate a reset signal on its second time-out. Once the Watchdog Timer has
been configured, the lock register can be written to prevent the timer configuration from being
inadvertently altered.
The LM3S5G31 microcontroller has two Watchdog Timer modules: Watchdog Timer 0 uses the
system clock for its timer clock; Watchdog Timer 1 uses the PIOSC as its timer clock. The Stellaris
Watchdog Timer module has the following features:
■ 32-bit down counter with a programmable load register
■ Separate watchdog clock with an enable
■ Programmable interrupt generation logic with interrupt masking
■ Lock register protection from runaway software
■ Reset generation logic with an enable/disable
■ User-enabled stalling when the microcontroller asserts the CPU Halt flag during debug
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July 03, 2014
Texas Instruments-Production Data