LM3S1968 Datasheet, PDF (603/709 Pages) List of Unclassifed Manufacturers – Microcontroller

Stellaris^® LM3S1968 Microcontroller
Figure 17-1. QEI Block Diagram
PhA
PhB
IDX
Control & Status
QEICTL
QEISTAT
Velocity
Predivider
clk
Quadrature
Encoder _dir
QEILOAD
Velocity Timer
QEITIME
Velocity Accumulator
QEICOUNT
QEISPEED
QEIMAXPOS
Position Integrator
QEIPOS
QEIINTEN
Interrupt Control
QEIRIS
QEIISC
Interrupt
17.2
Signal Description
Table 17-1 on page 603 and Table 17-2 on page 603 list the external signals of the QEI module and
describe the function of each. The QEI signals are alternate functions for some GPIO signals and
default to be GPIO signals at reset. The column in the table below titled "Pin Assignment" lists the
possible GPIO pin placements for these QEI signals. The AFSEL bit in the GPIO Alternate Function
Select (GPIOAFSEL) register (page 309) should be set to choose the QEI function. For more
information on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 286.
Table 17-1. QEI Signals (100LQFP)
Pin Name
Pin Number Pin Type Buffer Type^a Description
IDX0
10
I
TTL
QEI module 0 index.
IDX1
61
I
TTL
QEI module 1 index.
PhA0
25
I
TTL
QEI module 0 phase A.
PhA1
37
I
TTL
QEI module 1 phase A.
PhB0
47
I
TTL
QEI module 0 phase B.
PhB1
36
I
TTL
QEI module 1 phase B.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
Table 17-2. QEI Signals (108BGA)
Pin Name
IDX0
IDX1
PhA0
PhA1
Pin Number
G1
H12
L1
L7
Pin Type
I
I
I
I
Buffer Type^a Description
TTL
QEI module 0 index.
TTL
QEI module 1 index.
TTL
QEI module 0 phase A.
TTL
QEI module 1 phase A.
July 15, 2014
603
Texas Instruments-Production Data