LM3S8962 Datasheet, PDF (496/620 Pages) List of Unclassifed Manufacturers – Microcontroller

Analog Comparator
18
18.1
18.2
Analog Comparator
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S8962 controller provides one analog comparator that can be configured to drive an output
or generate an interrupt or ADC event.
Note: Not all comparators have the option to drive an output pin. See the Comparator Operating
Mode tables for more information.
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.
Block Diagram
Figure 18-1. 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
interrupt
Voltage
Ref
internal
bus
ACREFCTL
Functional Description
Important: It is recommended that the Digital-Input enable (the GPIODEN bit in the GPIO module)
for the analog input pin be disabled to prevent excessive current draw from the I/O
pads.
The comparator compares the VIN- and VIN+ inputs to produce an output, VOUT.
VIN- < VIN+, VOUT = 1
VIN- > VIN+, VOUT = 0
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September 02, 2007
Preliminary