LM3S301 Luminary Micro, Inc, LM3S301 Datasheet - Page 297

• Manufacturer Part Number: LM3S301
• Description: Lm3s301 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

14
14.1
14.2
July 5, 2006
1.Not all comparators have the option to drive an output pin. See Table 14-1 and Table 14-2 for more
information.
Analog Comparators
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
The LM3S301 controller provides two independent integrated analog comparators that can be
configured to drive an output
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 14-1. Analog Comparator Module Block Diagram
Functional Description
Important:
An individual external reference voltage
A shared single external reference voltage
A shared internal reference voltage
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+
C1-
C1+
C0-
bus
1
or generate an interrupt or ADC event.
ACREFCTL
Voltage
Ref
Preliminary
-ve input
+ve input
+ve input (alternate)
reference input
-ve input
+ve input
+ve input (alternate)
reference input
ACSTAT1
ACSTAT0
ACCTL1
ACCTL0
Comparator 1
Comparator 0
interrupt
interrupt
trigger
trigger
output
output
C1o
trigger
interrupt
C0o
trigger
interrupt
LM3S301 Data Sheet
297