LM3S308 Datasheet, PDF (35/537 Pages) Texas Instruments – ARM and Thumb are registered trademarks and Cortex is a trademark

Stellaris^® LM3S308 Microcontroller
1.4.1.5
1.4.1.6
1.4.2
1.4.2.1
1.4.3
1.4.3.1
1.4.3.2
System Control Block (SCB) (see page 85)
The SCB provides system implementation information and system control, including configuration,
control, and reporting of system exceptions.
Memory Protection Unit (MPU) (see page 85)
The MPU supports the standard ARMv7 Protected Memory System Architecture (PMSA) model.
The MPU provides full support for protection regions, overlapping protection regions, access
permissions, and exporting memory attributes to the system.
Motor Control Peripherals
To enhance motor control, the LM3S308 controller features Pulse Width Modulation (PWM) outputs.
PWM
Pulse width modulation (PWM) is a powerful technique for digitally encoding analog signal levels.
High-resolution counters are used to generate a square wave, and the duty cycle of the square
wave is modulated to encode an analog signal. Typical applications include switching power supplies
and motor control.
On the LM3S308, PWM motion control functionality can be achieved through:
■ The motion control features of the general-purpose timers using the CCP pins
CCP Pins (see page 270)
The General-Purpose Timer Module's CCP (Capture Compare PWM) pins are software programmable
to support a simple PWM mode with a software-programmable output inversion of the PWM signal.
Analog Peripherals
To handle analog signals, the LM3S308 microcontroller offers an Analog-to-Digital Converter (ADC).
For support of analog signals, the LM3S308 microcontroller offers one analog comparator.
ADC (see page 324)
An analog-to-digital converter (ADC) is a peripheral that converts a continuous analog voltage to a
discrete digital number.
The LM3S308 ADC module features 10-bit conversion resolution and supports eight input channels,
plus an internal temperature sensor. Four buffered sample sequences allow rapid sampling of up
to eight analog input sources without controller intervention. Each sample sequence provides flexible
programming with fully configurable input source, trigger events, interrupt generation, and sequence
priority.
Analog Comparators (see page 474)
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S308 microcontroller provides one analog comparator that can be configured to drive an
output or generate an interrupt or ADC event.
A comparator can compare a test voltage against any one of these voltages:
■ An individual external reference voltage
June 18, 2012
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