LM3S310 Luminary Micro, Inc, LM3S310 Datasheet - Page 268

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

Analog Comparators
13.2.1
268
Table 13-2. Comparator 1 Operating Modes
a. C1o and C1+ signals share a single pin and may only be used as one or the other.
Table 13-3. Comparator 2 Operating Modes
a. C2o and C2+ signals share a single pin and may only be used as one or the other.
Internal Reference Programming
The structure of the internal reference is shown in Figure 13-3. This is controlled by a single
configuration register (ACREFCTL). Table 13-4 shows the programming options to develop
specific internal reference values, to compare an external voltage against a particular voltage
generated internally.
Figure 13-3. Comparator Internal Reference Structure
Table 13-4. Internal Reference Voltage and ACREFCTL Field Values
00
01
10
11
00
01
10
11
EN Bit Value
ACCNTL1
ACCNTL2
EN=0
ASRCP
ASRCP
ACREFCTL Register
VREF
RNG
EN
RNG Bit Value
RNG=X
AVDD
VIN-
VIN-
C1-
C1-
C1-
C1-
C2-
C2-
C2-
C2-
8R
Preliminary
0 V (GND) for any value of VREF; however, it is recommended that
RNG=1 and VREF=0 for the least noisy ground reference.
R
Output Reference Voltage Based on VREF Field Value
15
R
C1o/C1+
C2o/C2+
reserved
reserved
VIN+
VIN+
C0+
Vref
C0+
Vref
14
•••
Decoder
•••
Comparator 1
Comparator 2
a
a
R
1
R
0
C1o/C1+
C1o/C1+
C1o/C1+
C1o/C1+
C2o/C2+
C2o/C2+
C2o/C2+
C2o/C2+
Output
Output
8R
internal
reference
Interrupt
Interrupt
yes
yes
yes
yes
yes
yes
yes
yes
July 5, 2006