Juno Step Motor Control IC User Guide
47
8
8.Microstep Waveform
Generation
In This Chapter
Command Position
Microsteps Per Full Step
Drive and Holding Current
Encoder Feedback
Settable Parameters
Signal Processing
Figure 8-1:
Microstepping
Waveforms
Juno step motor control ICs generate sinusoidal waveforms consisting of phase A and phase B outputs separated by 90
degrees. This is shown in
. The characteristics of these waveforms are determined by the input command
position along with other user-controlled settings or signals such as the number of microsteps per full step, the drive
current, and the
AtRest
signal.
8.1
Command Position
Three position command sources are available; pulse & direction signal input, direct input SPI, and internal profile
generation.
When pulse & direction is selected as the command source the incoming
Pulse
&
Direction
signals are processed by Juno
and the resultant count is stored in a 32 bit position register. Pulse & direction input is a popular and easy to use method
to continuously stream a commanded position to the Juno IC. For more information on signal format and timing, see
Direct-input SPI is an alternate available method of position command input. When direct-input SPI is selected the user
continuously streams a signed 16-bit word containing the relative position change from the previous SPI direct input
command. As for pulse & direction signal input, these direct input SPI commands are continuously processed and the
resultant count is maintained in a 32 bit position register.
When internal profile generation is selected the position commands come from Juno’s profile generator which is in turn
controlled by serial port commands specifying the profile acceleration, maximum velocity, and deceleration. For detailed
information on Juno’s profile generator refer to
2-Phase Microstepping
Phase A
Phase B
90
°
