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LM3S1H11 Datasheet, PDF (827/956 Pages) Texas Instruments – Stellaris® LM3S1H11 Microcontroller
Stellaris® LM3S1H11 Microcontroller
Table 17-3. Internal Reference Voltage and ACREFCTL Field Values (continued)
ACREFCTL Register
EN Bit
Value
RNG Bit Value Output Reference Voltage Based on VREF Field Value
RNG=0 Total resistance in ladder is 31 R.
VIREF = VDDA × RVREF
EN=1
RNG=1
TTohteVVVVVVVVVVVVVVVVVVVVVVVVVVValrIIIIIIIIIIIIIIIIIIIIIIIIIIIarRRRRRRRRRRRRRRRRRRRRRRRRRRRenEEEEEEEEEEEEsEEEEEEEEEEEEEEEgiFFFFFFFFFFFFFFFFFFFFFFFFFFFsetaonf===========================cineteVVVVVVVVVVVVVVVVVVVVVV000000000inrnDDDDDDDDDDDDDDDDDDDDDD.........laaDDDDDDDDDDDDDDDDDDDDDD888888111ldAAAAAAAAAAAAAAAAAAAAAArd444555555eef××××××××××××××××××××××e333r r++++++iseVVVVVRRRRRRRRRRR((((((×××n2VVVVVVc000000RRRRR3VVVVVVVVVVVRRRRRRRRRR2222eRRRRRRVVVRRRRRRRRRRR......REEEEETTTTTTTTTTTT3333iEEEEEEEEEEEEEEEEEnRRR.111111FFFFFFFFFFFFFFFF333333FFFFFFtEEEh000000111111iFFFs666666++++++mo××××××888888deVVVVVV))))))isRRRRRR0EEEEEE.8FFFFFF5-2.448 V.
VIREF = V0D.D1A4×3 V×R2VE3RFEF
VIREF = 0.143 ×2V3REF
VIREF = 0.143 × VREF
17.4
The range of internal reference for this mode is 0-2.152 V.
Initialization and Configuration
The following example shows how to configure an analog comparator to read back its output value
from an internal register.
1. Enable the analog comparator clock by writing a value of 0x0010.0000 to the RCGC1 register
in the System Control module (see page 245).
2. Enable the clock to the appropriate GPIO modules via the RCGC2 register (see page 254). To
find out which GPIO ports to enable, refer to Table 19-5 on page 860.
3. In the GPIO module, enable the GPIO port/pin associated with the input signals as GPIO inputs.
To determine which GPIO to configure, see Table 19-4 on page 854.
4. Configure the PMCn fields in the GPIOPCTL register to assign the analog comparator output
signals to the appropriate pins (see page 442 and Table 19-5 on page 860).
January 23, 2012
827
Texas Instruments-Production Data