LM3S5K31 Datasheet, PDF (973/1121 Pages) Texas Instruments – Stellaris® LM3S5K31 Microcontroller

Stellaris^® LM3S5K31 Microcontroller
Register 1: QEI Control (QEICTL), offset 0x000
This register contains the configuration of the QEI module. Separate enables are provided for the
quadrature encoder and the velocity capture blocks; the quadrature encoder must be enabled in
order to capture the velocity, but the velocity does not need to be captured in applications that do
not need it. The phase signal interpretation, phase swap, Position Update mode, Position Reset
mode, and velocity predivider are all set via this register.
QEI Control (QEICTL)
QEI0 base: 0x4002.C000
QEI1 base: 0x4002.D000
Offset 0x000
Type R/W, reset 0x0000.0000
31
30
29
28
27
Type
Reset
Type
Reset
RO
RO
0
0
15
14
reserved
RO
RO
0
0
RO
RO
RO
0
0
0
13
12
11
FILTEN STALLEN INVI
R/W
R/W
R/W
0
0
0
26
25
reserved
RO
RO
0
0
10
INVB
R/W
0
9
INVA
R/W
0
24
23
22
21
20
19
18
17
16
FILTCNT
RO
RO
RO
RO
RO
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
0
8
7
6
5
4
3
2
1
0
VELDIV
VELEN RESMODE CAPMODE SIGMODE SWAP ENABLE
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
0
Bit/Field
31:20
19:16
15:14
13
Name
reserved
FILTCNT
reserved
FILTEN
Type
RO
R/W
RO
R/W
Reset
0x000
0x0
0x0
0
Description
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.
Input Filter Prescale Count
This field controls the frequency of the input update.
When this field is clear, the input is sampled after 2 system clocks. When
this field ix 0x1, the input is sampled after 3 system clocks. Similarly,
when this field is 0xF, the input is sampled after 17 clocks.
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.
Enable Input Filter
Value Description
0 The QEI inputs are not filtered.
1 Enables the digital noise filter on the QEI input signals. Inputs
must be stable for 3 consecutive clock edges before the edge
detector is updated.
12
STALLEN
R/W
0
Stall QEI
Value Description
0 The QEI module does not stall when the microcontroller is
stopped by a debugger.
1 The QEI module stalls when the microcontroller is stopped by
a debugger.
January 20, 2012
973
Texas Instruments-Production Data