LM3S8938 Datasheet, PDF (485/550 Pages) List of Unclassifed Manufacturers – Microcontroller

LM3S8938 Microcontroller
18.2.1
Table 18-3. Comparator 2 Operating Modes
ACCNTL2 Comparator 2
ASRCP
00
VIN- VIN+
Output Interrupt ADC Trigger
C2- C2o/C2+^a C2o/C2+ yes
yes
01
C2- C0+ C2o/C2+ yes
yes
10
C2- Vref C2o/C2+ yes
yes
11
C2- reserved C2o/C2+ yes
yes
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 18-3 on page 485. This is controlled by a
single configuration register (ACREFCTL). Table 18-4 on page 485 shows the programming options
to develop specific internal reference values, to compare an external voltage against a particular
voltage generated internally.
Figure 18-3. Comparator Internal Reference Structure
AVDD
8R R
R
8R
R
R
•••
EN
VREF
RNG
15 14
•••
1
0
Decoder
internal
reference
Table 18-4. Internal Reference Voltage and ACREFCTL Field Values
ACREFCTL Register
Output Reference Voltage Based on VREF Field Value
EN Bit Value RNG Bit Value
EN=0
RNG=X
0 V (GND) for any value of VREF; however, it is recommended that RNG=1 and VREF=0
for the least noisy ground reference.
June 14, 2007
485
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