NXP Semiconductors
KTFRDM34933EVBUG
FRDM-34933EVB evaluation board
KTFRDM34933EVBUG
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User guide
Rev. 1.0 — 15 March 2017
26 / 39
where:
Counter_frequency = input frequency of the timer device
65536 = maximum value of TimerUnit_LDD counter (16-bit counter)
Adding 1 ensures that the 16-bit counter does not overflow (which is the point of the
formula)
For example if the Counter frequency is set to 187,500 Hz, the minimum speed is:
The MCU rounds the value down, so the result is 6 full-steps per second.
6.5.5.2 Setting the minimum full-stepping speed
This section describes how to change the input frequency of the TimerUnit_LDD
component.
1. Launch Processor Expert and select the LVHBridge component.
2. In the Processor Expert menu bar, set component visibility to
Advanced
.
3. In the Properties tab, find the
Motor Control
->
Stepper Motor
->
Manual timer
setting property and set the value to
Enabled
. If you do not see this property, make
sure that component visibility is set to Advanced (see
Figure 13
).
4. Set the TimerUnit_LDD frequency:
a. In the Components view, double-click the
TimerUnit_LDD
component.
b. Press the button in the Counter frequency field.
c. Set the frequency value (187.5 kHz in the illustration). The list of available
frequencies depends on the CPU component settings (with an external crystal as
the clock source and a core clock of 48 MHz).
d. Set the Allowed Error value at 10 % (see
Figure 15
).
