TM4C129XNCZAD Datasheet, PDF (2016/2191 Pages) Texas Instruments – Tiva Microcontroller

Quadrature Encoder Interface (QEI)
Bit/Field
3
2
1
0
Name
CAPMODE
SIGMODE
SWAP
ENABLE
Type
RW
RW
RW
RW
Reset
0
Description
Capture Mode
Note: When SIGMODE=1, the CAPMODE setting is not applicable and
is reserved.
Value Description
0 Only the PhA edges are counted.
1 The PhA and PhB edges are counted, providing twice the
positional resolution but half the range.
0
Signal Mode
Value Description
0 The internal PhA and PhB signals operate as quadrature phase
signals.
1 The internal PhA input operates as the clock (CLK) signal and
the internal PhB input operates as the direction (DIR) signal.
0
Swap Signals
Note if the INVA or INVB bit are set, the inversion of the signals occur
prior to the swap.
Value Description
0 No effect.
1 Swaps the PhAn and PhBn signals.
0
Enable QEI
Value Description
0 No effect.
1 Enables the quadrature encoder module.
Note:
Once the QEI module has been enabled by setting the
ENABLE bit, it cannot be disabled. The only way to clear the
ENABLE bit is to reset the module using the Quadrature
Encoder Interface Software Reset (SRQEI) register.
2016
Texas Instruments-Production Data
June 18, 2014