5.2.4 Power Control
The Stellaris
®
microcontroller provides an integrated LDO regulator that is used to provide power
to the majority of the microcontroller's internal logic. Figure 5-4 shows the power architecture.
An external LDO may not be used.
Note: VDDAmust be supplied with a voltage that meets the specification in Table 23-2 on page 981,
or the microcontroller does not function properly. VDDA is the supply for all of the analog
circuitry on the device, including the clock circuitry.
Figure 5-4. Power Architecture
Analog Circuits
I/O Buffers
Low-Noise
LDO
Internal
Logic and PLL
GND
GNDA
GNDA
VDDA
VDDA
VDDC
VDDC
LDO
+3.3V
GND
GND
GND
VDD
VDD
5.2.5 Clock Control
System control determines the control of clocks in this part.
5.2.5.1 Fundamental Clock Sources
There are multiple clock sources for use in the microcontroller:
■ Precision Internal Oscillator (PIOSC). The precision internal oscillator is an on-chip clock
source that is the clock source the microcontroller uses during and following POR. It does not
require the use of any external components and provides a clock that is 16 MHz ±1% at room
temperature and ±3% across temperature. The PIOSC allows for a reduced system cost in
July 24, 2012182
Texas Instruments-Production Data
System Control
OBSOLETE: TI has discontinued production of this device.
