Motor Output
Juno Step Motor Control IC User Guide
65
10
10.2.3 Signal Processing
As shown in the table below two PWM magnitude and two PWM sign signals are output to interface between the Juno
IC and the amplifier circuitry:
There are a wide variety of switching amplifier components and designs that can be used with Juno’s PWM High/Low
output mode. See
Application Notes — MC74113 & MC75113
, for schematic examples.
10.3 AmplifierEnable
Whether the motor output mode is set to PWM High/Low or Sign/Magnitude PWM, the Juno IC provides an
AmplifierEnable
signal output that indicates whether the external amplifier circuitry should be active or not. While not
all external amplifiers will require or provide such an input control, this signal is useful for general safety purposes, as
well as to simplify the task of ensuring startup without jogging the motor after power-up.
The output of this signal is affected by whether the motor output module is enabled and whether the brake function
is active. By default the motor output module is disabled and must be enabled by the user via serial host command or
NVRAM initialization command. During operations the motor output may become disabled by safety related event
processing. For more information on event processing refer to
Section 12.3, “Event Action Processing”
If either the motor output module is enabled or if the brake function is active than the
AmplifierEnable
signal is active.
If both the motor output module is disabled and the brake function is inactive than the
AmplifierEnable
signal is inactive.
10.4 Brake
The MC78113
Brake
signal input provides a high speed PWM output disable that may be useful for safety protection
when the motor output mode is set to PWM High/Low. When this input is active PWM output is driven to one of
two user programmable states; a fully disabled state or a braking state. PWM operation is normal when this signal is
inactive.
In the fully disabled state all switches for the selected motor type are open, meaning that all high and low control
signals are driven inactive and the
AmplifierEnable
signal is inactive. In the braking state all of the high-side switch control
signals are driven inactive, all of the low-side switch signals are active, and the
AmplifierEnable
signal is active, thereby
closing the lower side switches.
Signal
64-Pin
TQFP
Pin #
56-Pin
VQFN
Pin #
Description
PWMMagA
56
49
Digital PWM magnitude output for the step motor’s phase A H-bridge
switching amplifier
PWMSignA
55
48
Digital sign output for the step motor’s phase A H-bridge switching
amplifier
PWMMagC
51
45
Digital PWM magnitude output for the step motor’s phase B H-bridge
switching amplifier
PWMSignC
50
44
Digital sign output for the step motor’s phase B H-bridge switching
amplifier
