Datasheet

– Logging of up to four tamper events

– Optional BBRAM erase on tamper detection

– Tamper wake from hibernate capability

– Hibernation clock input failure detect with a switch to the internal oscillator on detection

■ RTC operational and hibernation memory valid as long as V

or V

BAT

is valid

■ Low-battery detection, signaling, and interrupt generation, with optional wake on low battery

■ GPIO pin state can be retained during hibernation

■ Clock source from an internal low frequency oscillator (HIB LFIOSC) or a 32.768-kHz external

crystal or oscillator

■ Sixteen 32-bit words of battery-backed memory to save state during hibernation

■ Programmable interrupts for:

– RTC match

– External wake

– Low battery

1.3.9.6 Watchdog Timers (see page 1152)

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 TM4C129ENCPDT Watchdog

Timer can generate an interrupt, a non-maskable 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

timeout. Once the Watchdog Timer has been configured, the lock register can be written to prevent

the timer configuration from being inadvertently altered.

The TM4C129ENCPDT 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

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 and optional NMI function

■ 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

1.3.9.7 Programmable GPIOs (see page 750)

General-purpose input/output (GPIO) pins offer flexibility for a variety of connections. The

TM4C129ENCPDT GPIO module is comprised of 15 physical GPIO blocks, each corresponding to

June 18, 201478

Texas Instruments-Production Data

Architectural Overview