LM3S310 Luminary Micro, Inc, LM3S310 Datasheet - Page 267

• Manufacturer Part Number: LM3S310
• Description: Lm3s310 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

13.2
July 5, 2006
Functional Description
Important:
The comparator compares the VIN- and VIN+ inputs to produce an output, VOUT.
As shown in Figure 13-2, the input source for VIN- is an external input. In addition to an external
input, input sources for VIN+ can be the +ve input of comparator 0 or an internal reference.
Figure 13-2. Structure of Comparator Unit
A comparator is configured through two status/control registers (ACCTL and ACSTAT). The
internal reference is configured through one control register (ACREFCTL). Interrupt status and
control is configured through three registers (ACMIS, ACRIS, and ACINTEN). The operating
modes of the comparators are shown in Table 13-1, Table 13-2 and Table 13-3.
Typically, the comparator output is used internally to generate controller interrupts. It may also be
used to drive an external pin.
Important:
Table 13-1. Comparator 0 Operating Modes
00
01
10
11
ACCNTL0
ASRCP
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.
Certain register bit values must be set before using the analog comparators. The
proper pad configuration for the comparator input and output pins are described in
Table 8-1 on page 107.
+ve input (alternate)
reference input
VIN-
+ve input
C0-
C0-
C0-
C0-
-ve input
Preliminary
0
1
2
ACCTL
reserved
VIN+
C0+
C0+
Vref
Comparator 0
CINV
ACSTAT
Output
IntGen
C0o
C0o
C0o
C0o
output
LM3S310 Data Sheet
Interrupt
yes
yes
yes
yes
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