LM4F232H5QCFIG Datasheet, PDF (1235/1472 Pages) Texas Instruments – Stellaris® LM4F232H5QC Microcontroller

Stellaris^® LM4F232H5QC Microcontroller
Table 19-1. Analog Comparators Signals (100LQFP) (continued)
Pin Name
Pin Number Pin Mux / Pin Pin Type Buffer Type^a Description
Assignment
C1-
25
PC4
I
Analog Analog comparator 1 negative input.
C1o
41
PF1 (9)
O
TTL
Analog comparator 1 output.
C2+
87
PG6
I
Analog Analog comparator 2 positive input.
C2-
88
PG7
I
Analog Analog comparator 2 negative input.
C2o
42
PF2 (9)
O
TTL
Analog comparator 2 output.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
19.3
Functional Description
The comparator compares the VIN- and VIN+ inputs to produce an output, VOUT.
VIN- < VIN+, VOUT = 1
VIN- > VIN+, VOUT = 0
As shown in Figure 19-2 on page 1235, the input source for VIN- is an external input, Cn-. In addition
to an external input, Cn+, input sources for VIN+ can be the C0+ or an internal reference, V_IREF.
Figure 19-2. Structure of Comparator Unit
- ve input
0
+ ve input
1
+ ve input (alternate)
2
reference input
CINV
output
IntGen
TrigGen
ACCTL
ACSTAT
A comparator is configured through two status/control registers, Analog Comparator Control
(ACCTL) and Analog Comparator Status (ACSTAT). The internal reference is configured through
one control register, Analog Comparator Reference Voltage Control (ACREFCTL). Interrupt
status and control are configured through three registers, Analog Comparator Masked Interrupt
Status (ACMIS), Analog Comparator Raw Interrupt Status (ACRIS), and Analog Comparator
Interrupt Enable (ACINTEN).
Typically, the comparator output is used internally to generate an interrupt as controlled by the ISEN
bit in the ACCTL register. The output may also be used to drive an external pin, Co or generate an
analog-to-digital converter (ADC) trigger.
Important: The ASRCP bits in the ACCTL register must be set before using the analog comparators.
November 08, 2011
Texas Instruments-Advance Information
1235