LM3S101_0610 Datasheet, PDF (262/300 Pages) List of Unclassifed Manufacturers – Microcontroller

Analog Comparators
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
-ve input
+ve input ⁰
+ve input (alternate) ¹
CINV
output
IntGen
reference input ²
ACCTL
ACSTAT
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 and Table 13-2.
Typically, the comparator output is used internally to generate controller interrupts. It may also be
used to drive an external pin.
Important: 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 101.
Table 13-1. Comparator 0 Operating Modes
ACCNTL0
Comparator 0
ASRCP
00
01
10
11
VIN-
C0-
C0-
C0-
C0-
VIN+
C0+
C0+
Vref
reserved
Output
C0o/C1-
C0o/C1-
C0o/C1-
C0o/C1-
Table 13-2. Comparator 1 Operating Modes
ACCNTL1
Comparator 1
ASRCP
00
01
10
VIN-
C0o/C1-^a
C0o/C1-
C0o/C1-
VIN+
n/a
C0+
Vref
Output
n/a
n/a
n/a
Interrupt
yes
yes
yes
yes
Interrupt
yes
yes
yes
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October 5, 2006
Preliminary