LM3S2939 Datasheet, PDF (597/749 Pages) Texas Instruments – Stellaris® LM3S2939 Microcontroller

Stellaris^® LM3S2939 Microcontroller
16.1
Block Diagram
Figure 16-1. Analog Comparator Module Block Diagram
C2-
-ve input _{Comparator 2}
C2+
+ve input
output
<none>
+ve input (alternate)
ACCTL2
trigger
trigger
ACSTAT2
interrupt
reference input
C1-
-ve input _{Comparator 1}
C1+
+ve input
output
C1o
+ve input (alternate)
ACCTL1
trigger
trigger
ACSTAT1
interrupt
reference input
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
16.2
Signal Description
Table 16-1 on page 597 and Table 16-2 on page 598 list the external signals of the Analog Comparators
and describe the function of each. The Analog Comparator output signals are alternate functions
for some GPIO signals and default to be GPIO signals 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 309) should be set
to choose the Analog Comparator function. The positive and negative input signals are configured
by clearing the DEN bit in the GPIO Digital Enable (GPIODEN) register. For more information on
configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 285.
Table 16-1. Analog Comparators Signals (100LQFP)
Pin Name
Pin Number Pin Type Buffer Type^a Description
C0+
90
I
Analog Analog comparator 0 positive input.
C0-
92
I
Analog Analog comparator 0 negative input.
C0o
58
O
TTL
Analog comparator 0 output.
C1+
24
I
Analog Analog comparator 1 positive input.
C1-
91
I
Analog Analog comparator 1 negative input.
C1o
46
O
TTL
Analog comparator 1 output.
June 18, 2012
597
Texas Instruments-Production Data