LM3S1G21 Datasheet, PDF (174/955 Pages) Texas Instruments – Stellaris® LM3S1G21 Microcontroller

System Control
5.2.1
5.2.2
5.2.2.1
■ System control (Run, Sleep, and Deep-Sleep modes), see “System Control” on page 187
Device Identification
Several read-only registers provide software with information on the microcontroller, such as version,
part number, SRAM size, Flash memory size, and other features. See the DID0 (page 192), DID1
(page 219), DC0-DC9 (page 221) and NVMSTAT (page 238) registers.
Reset Control
This section discusses aspects of hardware functions during reset as well as system software
requirements following the reset sequence.
Reset Sources
The LM3S1G21 microcontroller has six sources of reset:
1. Power-on reset (POR) (see page 175).
2. External reset input pin (RST) assertion (see page 175).
3. Internal brown-out (BOR) detector (see page 177).
4. Software-initiated reset (with the software reset registers) (see page 177).
5. A watchdog timer reset condition violation (see page 178).
6. MOSC failure (see page 179).
Table 5-3 provides a summary of results of the various reset operations.
Table 5-3. Reset Sources
Reset Source
Core Reset?
JTAG Reset?
On-Chip Peripherals Reset?
Power-On Reset
Yes
Yes
Yes
RST
Yes
Yes
Yes
Brown-Out Reset
Yes
Yes
Yes
Software System Request
Yes
Yes
Yes
Reset using the SYSRESREQ
bit in the APINT register.
Software System Request
Yes
No
No
Reset using the VECTRESET
bit in the APINT register.
Software Peripheral Reset
No
Yes
Yes^a
Watchdog Reset
Yes
Yes
Yes
MOSC Failure Reset
Yes
Yes
Yes
a. Programmable on a module-by-module basis using the Software Reset Control Registers.
After a reset, the Reset Cause (RESC) register is set with the reset cause. The bits in this register
are sticky and maintain their state across multiple reset sequences, except when an internal POR
is the cause, in which case, all the bits in the RESC register are cleared except for the POR indicator.
A bit in the RESC register can be cleared by writing a 0.
174
January 22, 2012
Texas Instruments-Production Data