LM3S5D91 Datasheet, PDF (1057/1340 Pages) Texas Instruments – Stellaris® LM3S5D91 Microcontroller

Stellaris^® LM3S5D91 Microcontroller
19.1
Block Diagram
Figure 19-1. Analog Comparator Module Block Diagram
C2-
-ve input _{Comparator 2}
C2+
+ve input
output
C2o
+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
19.2
Signal Description
The following table lists the external signals of the Analog Comparators and describes 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 Mux/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 425) should be set to choose the
Analog Comparator function. The number in parentheses is the encoding that must be programmed
into the PMCn field in the GPIO Port Control (GPIOPCTL) register (page 443) to assign the Analog
Comparator signal to the specified GPIO port pin. 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 400.
Table 19-1. Analog Comparators Signals (100LQFP)
Pin Name
C0+
C0-
Pin Number Pin Mux / Pin
Assignment
90
PB6
92
PB4
Pin Type
I
I
Buffer Type^a Description
Analog
Analog
Analog comparator 0 positive input.
Analog comparator 0 negative input.
January 22, 2012
Texas Instruments-Production Data
1057