CY545 Stepper System Controller
STOPPED
www.ControlChips.com
The STOPPED signal is a status output from the CY545, indicating whether the motor is
stepping or not. At the beginning of a motion, from either a Go or Position command, the
STOPPED signal is brought low. It will continue to stay low for the duration of that motion. At the
end of the motion, the STOPPED signal is brought high again. The low-to-high transition on
STOPPED indicates when the motion is over, and the high level indicates that the motor is no
longer moving. A typical waveform is shown below.
The STOPPED signal may be used as a motion complete indication to the host system. It may
also control the power selection for the stepper motor power driver, switching automatically
between a high power selection while stepping, and a parking power selection while stopped.
This can provide maximum torque during motions and provide holding torque while the motor is
not moving, in order to prevent overheating of the motor. The CY545 automatically delays for 5
milliseconds after the last step, before bringing the STOPPED signal high again. This allows the
motor to settle into its final position before the high driving power is removed.
SLEW
Another status output from the CY545 is the SLEW signal, which indicates when the selected
step rate (Rate parameter) has been achieved. This signal is normally high, and goes low while
the CY545 is stepping the motor without acceleration or deceleration. A typical waveform is
shown below. Notice that the time between STOPPED being low and SLEW being low
represents the time to accelerate or decelerate the motor.
The SLEW signal may also be used as an input. If this signal is driven low before the beginning
of a motion, the CY545 will enter the continuous stepping mode. In this mode, it will accelerate
© 2002 Cybernetic Micro Systems
69
Chapter 16 - Timing and Control
ETC [ ETC ]
