LM3S308 Luminary Micro, Inc, LM3S308 Datasheet - Page 367

• Manufacturer Part Number: LM3S308
• Description: Lm3s308 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

15
15.1
15.2
June 04, 2008
Analog Comparator
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S308 controller provides one analog comparator that can be configured to drive an output
or generate an interrupt or ADC event.
Note:
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.
Block Diagram
Figure 15-1. Analog Comparator Module Block Diagram
Functional Description
Important:
The comparator compares the VIN- and VIN+ inputs to produce an output, VOUT.
An individual external reference voltage
A shared single external reference voltage
A shared internal reference voltage
Not all comparators have the option to drive an output pin. See the Comparator Operating
Mode tables in “Functional Description” on page 367 for more information.
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.
internal
C0+
C0-
bus
ACREFCTL
Preliminary
Voltage
Ref
-ve input
+ve input
+ve input (alternate)
reference input
ACSTAT0
ACCTL0
Comparator 0
interrupt
output
Interrupt Control
ACINTEN
interrupt
ACRIS
ACMIS
<none>
LM3S308 Microcontroller
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