LM3S6100 Datasheet, PDF (475/559 Pages) Texas Instruments – Stellaris® LM3S6100 Microcontroller

Stellaris^® LM3S6100 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.
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 to cause it to start
capturing a sample sequence.
The Stellaris^® Analog Comparators module has the following features:
■ One integrated analog comparator
■ Configurable for output to drive an output pin or generate an interrupt
■ 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-
C0+
internal
bus
-ve input _{Comparator 0}
+ve input
output
+ve input (alternate)
ACCTL0
ACSTAT0
interrupt
reference input
Voltage
Ref
ACREFCTL
C0o
Interrupt Control
ACRIS
ACMIS
ACINTEN
interrupt
Signal Description
Table 13-1 on page 476 and Table 13-2 on page 476 list the external signals of the Analog Comparators
and describe 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 the possible GPIO pin placements for the Analog Comparator signals. The AFSEL
bit in the GPIO Alternate Function Select (GPIOAFSEL) register (page 262) should be set to choose
the Analog Comparator function. The positive and negative input signal are configured by clearing
June 18, 2012
475
Texas Instruments-Production Data