TM4C1233H6PM Datasheet, PDF (210/1215 Pages) Texas Instruments – Tiva Microcontroller

System Control
5.2.2.5
5.2.2.6
The internal Brown-Out Reset timing is shown in “Power and Brown-Out” on page 1171.
Software Reset
Software can reset a specific peripheral or generate a reset to the entire microcontroller.
Peripherals can be individually reset by software via peripheral-specific reset registers available
beginning at System Control offset 0x500 (for example the Watchdog Timer Software Reset
(SRWD) register). If the bit position corresponding to a peripheral is set and subsequently cleared,
the peripheral is reset.
The entire microcontroller, including the core, can be reset by software by setting the SYSRESREQ
bit in the Application Interrupt and Reset Control (APINT) register. The software-initiated system
reset sequence is as follows:
1. A software microcontroller reset is initiated by setting the SYSRESREQ bit.
2. An internal reset is asserted.
3. The internal reset is deasserted and the microcontroller loads from memory the initial stack
pointer, the initial program counter, and the first instruction designated by the program counter,
and then begins execution.
The core only can be reset by software by setting the VECTRESET bit in the APINT register. The
software-initiated core reset sequence is as follows:
1. A core reset is initiated by setting the VECTRESET bit.
2. An internal reset is asserted.
3. The internal reset is deasserted and the microcontroller loads from memory the initial stack
pointer, the initial program counter, and the first instruction designated by the program counter,
and then begins execution.
The software-initiated system reset timing is shown in Figure 22-12 on page 1177.
Watchdog Timer Reset
The Watchdog Timer module's function is to prevent system hangs. The TM4C1233H6PM
microcontroller has two Watchdog Timer modules in case one watchdog clock source fails. One
watchdog is run off the system clock and the other is run off the Precision Internal Oscillator (PIOSC).
Each module operates in the same manner except that because the PIOSC watchdog timer module
is in a different clock domain, register accesses must have a time delay between them. The watchdog
timer can be configured to generate an interrupt or a non-maskable interrupt to the microcontroller
on its first time-out and to generate a reset on its second time-out.
After the watchdog's first time-out event, the 32-bit watchdog counter is reloaded with the value of
the Watchdog Timer Load (WDTLOAD) register and resumes counting down from that value. If
the timer counts down to zero again before the first time-out interrupt is cleared, and the reset signal
has been enabled, the watchdog timer asserts its reset signal to the microcontroller. The watchdog
timer reset sequence is as follows:
1. The watchdog timer times out for the second time without being serviced.
2. An internal reset is asserted.
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June 12, 2014
Texas Instruments-Production Data