LM3S5D91 Datasheet, PDF (652/1340 Pages) Texas Instruments – Stellaris® LM3S5D91 Microcontroller

Analog-to-Digital Converter (ADC)
Register 13: ADC Control (ADCCTL), offset 0x038
This register configures various ADC module attributes, including the ADC resolution and the voltage
reference. The resolution of the ADC defaults to 10-bit for backwards compatibility with other members
of the Stellaris family, but can be configured to 12-bit resolution. The voltage reference for the
conversion can be the internal 3.0-V reference, an external voltage reference in the range of 2.4 V
to 3.06 V, or an external voltage reference in the range of 0.8 V to 1.02 V.
ADC Control (ADCCTL)
ADC0 base: 0x4003.8000
ADC1 base: 0x4003.9000
Offset 0x038
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
RES
reserved
VREF
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
R/W
RO
RO
R/W
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
31:5
4
Name
reserved
RES
Type
Reset Description
RO 0x0000.000 Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
R/W
0
Sample Resolution
Value Description
1 The ADC returns 12-bit data to the FIFOs.
0 The ADC returns 10-bit data to the FIFOs.
3:2
reserved
RO
0x0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1:0
VREF
R/W
0x0
Voltage Reference Select
Value Description
0x0 Internal Reference
The internal reference as the voltage reference. The conversion
range is from 0 V to 3.0 V.
0x1 3.0 V External Reference
A 3.0 V external VREFA input is the voltage reference. The ADC
conversion range is 0.0 V to the voltage of the VREFA input.
0x2 Reserved
0x3 1.0 V External Reference
A 1.0 V external VREFA input is the voltage reference. The ADC
conversion range is 0.0 V to three times the voltage of the
VREFA input.
652
January 22, 2012
Texas Instruments-Production Data