LM3S1512 Luminary Micro, Inc, LM3S1512 Datasheet - Page 31

• Manufacturer Part Number: LM3S1512
• Description: Lm3s1512 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

1.4.2.2
1.4.3
1.4.3.1
1.4.3.2
July 25, 2008
wave is modulated to encode an analog signal. Typical applications include switching power supplies
and motor control.
On the LM3S1512, PWM motion control functionality can be achieved through:
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CCP Pins (see page 212)
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.
QEI (see page 424)
A quadrature encoder, also known as a 2-channel incremental encoder, converts linear displacement
into a pulse signal. By monitoring both the number of pulses and the relative phase of the two signals,
you can track the position, direction of rotation, and speed. In addition, a third channel, or index
signal, can be used to reset the position counter.
The Stellaris quadrature encoder with index (QEI) module interprets the code produced by a
quadrature encoder wheel to integrate position over time and determine direction of rotation. In
addition, it can capture a running estimate of the velocity of the encoder wheel.
Analog Peripherals
To handle analog signals, the LM3S1512 microcontroller offers an Analog-to-Digital Converter
(ADC).
For support of analog signals, the LM3S1512 microcontroller offers three analog comparators.
ADC (see page 265)
An analog-to-digital converter (ADC) is a peripheral that converts a continuous analog voltage to a
discrete digital number.
The LM3S1512 ADC module features 10-bit conversion resolution and supports two 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 411)
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S1512 microcontroller provides three independent integrated analog comparators 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:
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The comparator can provide its output to a device pin, acting as a replacement for an analog
comparator on the board, or it can be used to signal the application via interrupts or triggers to the
The motion control features of the general-purpose timers using the CCP pins
An individual external reference voltage
A shared single external reference voltage
A shared internal reference voltage
Preliminary
LM3S1512 Microcontroller
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