Performance Motion Devices Juno MC71112, User Manual

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Application Notes — MC74113 & MC75113
98
Juno Step Motor Control IC User Guide
15
15.5 Reset Signal
The MC74113 and MC75113 chips have a built-in power supervisory circuitry that generates an internal reset signal
when a power-on or brown-out condition occurs. As such, no external circuitry is needed to generate a reset input
pulse. An R-C circuit must be connected to this pin for noise immunity reasons.
The supervisor reset release delay time is typically 600 μ sec after the power-on or brown-out condition event is
removed. If need be, an external circuit may also drive this pin to assert a device reset. In this case, it is recommended
that this pin be driven by an open-drain device.
All digital output signals have an internal pullup except for
FaultOut
and the
PWM
signals
. See
Section 14.5.1, “Output
Signal Status During Power-up” for more information. If the
AmplifierEnable
and
FaultOut
signals are used they should
have an external pull down resistor to prevent any glitches during reset.
During the initialization period, the MC74113 and MC75113 are configured with the default initialization parameters
for communication, analog offsets, control loop gains etc. If necessary, the on chip non-volatile storage can be used
to store user-programmed initialization parameters. For more information see
Section 6.1, “Loading the NVRAM.”