LM3S1538 Luminary Micro, Inc, LM3S1538 Datasheet - Page 31

• Manufacturer Part Number: LM3S1538
• Description: Lm3s1538 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

1.4.2.2
1.4.3
1.4.3.1
1.4.4
1.4.4.1
July 26, 2008
wave is modulated to encode an analog signal. Typical applications include switching power supplies
and motor control.
On the LM3S1538, 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 411)
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 LM3S1538 microcontroller offers an Analog-to-Digital Converter
(ADC).
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 LM3S1538 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.
Serial Communications Peripherals
The LM3S1538 controller supports both asynchronous and synchronous serial communications
with:
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UART (see page 298)
A Universal Asynchronous Receiver/Transmitter (UART) is an integrated circuit used for RS-232C
serial communications, containing a transmitter (parallel-to-serial converter) and a receiver
(serial-to-parallel converter), each clocked separately.
The LM3S1538 controller includes three fully programmable 16C550-type UARTs that support data
transfer speeds up to 3.125 Mbps. (Although similar in functionality to a 16C550 UART, it is not
register-compatible.) In addition, each UART is capable of supporting IrDA.
The motion control features of the general-purpose timers using the CCP pins
Three fully programmable 16C550-type UARTs
Two SSI modules
Two I
2
C modules
Preliminary
LM3S1538 Microcontroller
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