Texas Instruments Stellaris, User Manual

Page: 28 / 45

28 November 4, 2009
Motor Running Configuration
Target Position
This parameter indicates the target position which is represented internally as a signed 24-bit
number. It starts at position 0 and can run to the positive maximum or negative minimum of the
range.
Maximum Current
This parameter sets the trip point for a hardware comparator. If the current exceeds this value, the
comparator triggers a fault and places the motor in a safe configuration.
Target Speed
This parameter sets the target speed of the motor. When moving, the motor accelerates up to this
speed and remains at this speed until near the target position, at which time it decelerates to a
stop. This value is in whole steps, so if Half-Stepping mode is used, then the actual stepping rate
applied to the motor will be twice this value.
It may be difficult to get the stepper motor up to maximum speed if it does not have a load.
Acceleration
This parameter is the rate at which the motor accelerates to reach the target speed. Larger values
work better if the motor has no load, avoiding the resonant frequencies. If the motor has much
load, then this value may need to be lowered.
ID Units Range Default
PARAM_TARGET_POS whole steps -8388608–8388607 0
ID Units Range Default
PARAM_MAX_CURRENT mA 1000–10000 4000
ID Units Range Default
PARAM_TARGET_SPEED steps/sec 10–10000 200
ID Units Range Default
PARAM_ACCEL steps/sec
2
100–60000 30000