Stellaris® Stepper Motor RDK User’s Manual
November 4, 2009 29
Deceleration
This parameter is the rate at which the motor decelerates from the target speed to stop at the 
target position. Typically, the motor can decelerate faster than accelerate since the load and 
friction are working to help decelerate the motor.
Motor Drive Configuration
Winding Resistance
This parameter sets the resistance of the winding. It should be obtained from the motor 
specification. This value is used in calculating the correct duty cycle if PWM mode is used.
PWM Frequency
If PWM mode is used, this parameter determines the PWM period.
Fixed Rise Time
If PWM mode is used, this parameter sets the amount of time at the beginning of a step that the 
winding is left with full voltage applied before PWM is used to control the current. By leaving the full 
voltage applied to the winding, the current rises as fast as possible, allowing it to reach the drive 
current faster.
Caution – If making adjustments to this value, do not exceed the motor’s rated current. Use lab 
equipment to measure the current in the winding when making adjustments to this value.
ID Units Range Default
PARAM_DECEL steps/sec
2
100–60000 60000
ID Units Range Default
PARAM_RESISTANCE mΩ 100–5000 750
ID Units Range Default
PARAM_PWM_FREQUENCY Hz 16000–32000 20000
ID Units Range Default
PARAM_FIXED_ON_TIME μS 1–10000 800