LM3S817 Datasheet, PDF (445/553 Pages) List of Unclassifed Manufacturers – Microcontroller

Stellaris^® LM3S817 Microcontroller
13
13.1
13.2
Analog Comparator
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
Note: Not all comparators have the option to drive an output pin. See the Comparator Operating
Mode tables in “Functional Description” on page 446 for more information.
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.
The Stellaris^® Analog Comparators module has the following features:
■ One integrated analog comparator
■ Configurable for output to drive an output pin, generate an interrupt, or initiate an ADC sample
sequence
■ Compare external pin input to external pin input or to internal programmable voltage reference
■ 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
Block Diagram
Figure 13-1. Analog Comparator Module Block Diagram
C0-
-ve input _{Comparator 0}
C0+
+ve input
output
C0o
+ve input (alternate)
ACCTL0
trigger
trigger
ACSTAT0
interrupt
reference input
internal
bus
Voltage
Ref
ACREFCTL
Interrupt Control
ACRIS
ACMIS
ACINTEN
interrupt
Signal Description
Table 13-1 on page 446 lists the external signals of the Analog Comparators and describes the
function of each. The Analog Comparator output signal is an alternate functions for a GPIO signal
and default to be a GPIO signal at reset. The column in the table below titled "Pin Assignment" lists
July 14, 2014
445
Texas Instruments-Production Data