LM3S315 Luminary Micro, Inc., LM3S315 Datasheet - Page 28

• Manufacturer Part Number: LM3S315
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

Architectural Overview
1.4.3
1.4.3.1
1.4.3.2
1.4.4
1.4.4.1
28
CCP Pins (“16-Bit PWM Mode” on page 162)
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 LM3S315 controller offers an Analog-to-Digital Converter (ADC) and
an analog comparator.
ADC (Section 11 on page 208)
An analog-to-digital converter (ADC) is a peripheral that converts a continuous analog voltage to a
discrete digital number.
The Stellaris ADC module features 10-bit conversion resolution and supports foursix 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 Comparator (Section 14 on page 309)
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S315 controller provides one 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:
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
ADC to cause it to start capturing a sample sequence. The interrupt generation and ADC triggering
logic is separate. This means, for example, that an interrupt can be generated on a rising edge and
the ADC triggered on a falling edge.
Serial Communications Peripherals
The LM3S315 controller supports both asynchronous and synchronous serial communications
with two fully programmable 16C550-type UARTs and SSI serial communications.
UART (Section 12 on page 238)
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 LM3S315 controller includes two fully programmable 16C550-type UARTs that support data
transfer speeds up to 460.8 Kbps. (Although similar in functionality to a 16C550 UART, it is not
register compatible.)
Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs reduce CPU interrupt service loading.
The UART can generate individually masked interrupts from the RX, TX, modem status, and error
conditions. The module provides a single combined interrupt when any of the interrupts are
asserted and are unmasked.
An individual external reference voltage
A single external reference voltage
A shared internal reference voltage
Preliminary
April 27, 2007