LM3S817 Datasheet, PDF (38/553 Pages) List of Unclassifed Manufacturers – Microcontroller

Architectural Overview
1.4.3.2
1.4.4
1.4.4.1
1.4.4.2
The LM3S817 ADC module features 10-bit conversion resolution and supports six 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 445)
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S817 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
■ A shared single external reference voltage
■ A shared internal reference voltage
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 LM3S817 controller supports both asynchronous and synchronous serial communications with:
■ Two fully programmable 16C550-type UARTs
■ One SSI module
UART (see page 367)
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 LM3S817 controller includes two 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.)
Separate 16x8 transmit (TX) and 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.
SSI (see page 407)
Synchronous Serial Interface (SSI) is a four-wire bi-directional full and low-speed communications
interface.
The LM3S817 controller includes one SSI module that provides the functionality for synchronous
serial communications with peripheral devices, and can be configured to use the Freescale SPI,
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July 14, 2014
Texas Instruments-Production Data