LM3S2110-IQN20-A0 Luminary Micro, Inc., LM3S2110-IQN20-A0 Datasheet - Page 28

• Manufacturer Part Number: LM3S2110-IQN20-A0
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

Architectural Overview
1.4.2.1
1.4.3
1.4.3.1
1.4.4
28
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 LM3S2110, PWM motion control functionality can be achieved through:
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PWM Pins (see page 401)
The LM3S2110 PWM module consists of one PWM generator blocks and a control block. Each
PWM generator block contains one timer (16-bit down or up/down counter), two comparators, a
PWM signal generator, a dead-band generator, and an interrupt. The control block determines the
polarity of the PWM signals, and which signals are passed through to the pins.
Each PWM generator block produces two PWM signals that can either be independent signals or
a single pair of complementary signals with dead-band delays inserted. The output of the PWM
generation blocks are managed by the output control block before being passed to the device pins.
CCP Pins (see page 181)
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
For support of analog signals, the LM3S2110 microcontroller offers three analog comparators.
Analog Comparators (see page 388)
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S2110 microcontroller provides three independent integrated analog comparators that can
be configured to drive an output or generate an interrupt .
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 to cause it to start
capturing a sample sequence.
Serial Communications Peripherals
The LM3S2110 controller supports both asynchronous and synchronous serial communications
with:
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Dedicated, flexible motion control hardware using the PWM pins
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
One fully programmable 16C550-type UART
Preliminary
November 29, 2007