LM3S2918 Luminary Micro, Inc, LM3S2918 Datasheet - Page 455

• Manufacturer Part Number: LM3S2918
• Description: Lm3s2918 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

17.2.1
July 26, 2008
Table 17-2. Comparator 1 Operating Modes
a. C1o and C1+ 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 17-3 on page 455. This is controlled by a
single configuration register (ACREFCTL). Table 17-3 on page 455 shows the programming options
to develop specific internal reference values, to compare an external voltage against a particular
voltage generated internally.
Figure 17-3. Comparator Internal Reference Structure
VREF
Table 17-3. Internal Reference Voltage and ACREFCTL Field Values
ACCNTL0
ASRCP
10
11
ACCNTL1
ASRCP
00
01
10
11
ACREFCTL Register
EN Bit Value
RNG
EN
EN=0
Comparator 0
VIN-
Comparator 1
VIN-
C0-
C0-
C1-
C1-
C1-
C1-
AVDD
RNG Bit Value
VIN+
reserved
VIN+
C1o/C1+
reserved
RNG=X
Vref
C0+
Vref
a
8R
Output
Output
C1o/C1+
C1o/C1+
C1o/C1+
C1o/C1+
C0o
C0o
Output Reference Voltage Based on VREF Field Value
0 V (GND) for any value of VREF; however, it is recommended that RNG=1 and VREF=0
for the least noisy ground reference.
15
Interrupt
R
Interrupt
yes
yes
yes
yes
yes
yes
14
Preliminary
ADCTrigger
Decoder
ADCTrigger
yes
yes
R
yes
yes
yes
yes
1
R
0
8R
LM3S2918 Microcontroller
internal
reference
455