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Signal Descriptions
41.2.11 Watchdog Timer
A watchdog timer is included. It ensures the algorithm is indicating motion in the shaft.
Two successive counts indicate proper operation and will reset the timer. The time-out
value is programmable. When a time-out occurs, an interrupt to the processor can be
generated.
41.3 Signal Descriptions
Four external signals are muxed to the four pins of a quad timer module. Two internal
signals can be connected to other SoC resources.
41.3.1 Phase A Input (PHASEA)
The PHASEA input can be connected to one of the phases from a two-phase shaft
quadrature encoder output. It is used by the quadrature decoder module in conjunction
with the PHASEB input to indicate a decoder increment has passed, and to calculate its
direction. PHASEA is the leading phase for a shaft rotating in the positive direction.
PHASEA is the trailing phase for a shaft rotating in the negative direction. It can also be
used as the single input when the quadrature decoder module is used as a single phase
pulse accumulator.
The PHASEA input can also be an input capture channel for one of the timer modules via
the Crossbar module (XBAR).
41.3.2 Phase B Input (PHASEB)
The PHASEB input is used as one of the phases from a two phase shaft quadrature
encoder output. It is used by the quadrature decoder module in conjunction with the
PHASEA input indicating a decoder increment has passed, and to calculate its direction.
PHASEB is the trailing phase for a shaft rotating in the positive direction. PHASEB is the
leading phase for a shaft rotating in the negative direction.
The PHASEB input can also be an input capture channel for one of the timer modules via
the Crossbar module (XBAR).
KV4x Reference Manual, Rev. 2, 02/2015
Preliminary
1044
Freescale Semiconductor, Inc.
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