LM3S316 Luminary Micro, Inc., LM3S316 Datasheet - Page 346

• Manufacturer Part Number: LM3S316
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

Analog Comparator
15.2.1
346
Figure 15-2. 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 15-1.
Typically, the comparator output is used internally to generate controller interrupts. It may also be
used to drive an external pin or generate an analog-to-digital converter (ADC) trigger.
Important:
Table 15-1. Comparator 0 Operating Modes
Internal Reference Programming
The structure of the internal reference is shown in Figure 15-3. This is controlled by a single
configuration register (ACREFCTL). Table 15-2 shows the programming options to develop
specific internal reference values, to compare an external voltage against a particular voltage
generated internally.
00
01
10
11
ACCNTL0
ASRCP
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 122.
+ve input (alternate)
reference input
+ve input
-ve input
VIN-
C0-
C0-
C0-
C0-
0
1
2
ACCTL
Preliminary
reserved
VIN+
C0+
C0+
Vref
CINV
Comparator 0
Output
C0o
C0o
C0o
C0o
ACSTAT
TrigGen
IntGen
output
Interrupt
yes
yes
yes
yes
ADC Trigger
April 27, 2007
yes
yes
yes
yes