User Manual

TMC5031-EVAL Manual / Firmware V1.00 (Rev. 1.00 / 2013-FEB-22) 25
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6.4.6 Microstep Wave Dialogue
The microstep wave dialogue has two tabs, one for motor 1 and the other one for motor 2. Each motor
driver of the TMC5031 provides a programmable look-up table for storing the microstep current wave.
Per default, the tables are pre-programmed with a sine wave, which is a good starting point for most
stepper motors. Reprogramming the table to a motor specific wave allows improved microstepping. In
order to minimize required memory and the amount of data to be programmed, only a quarter of the
wave becomes stored. The internal microstep table maps the microstep wave from 0° to 90°. It
becomes symmetrically extended to 360°.
The microstep wave dialogue for each motor has four input fields (a1, a3, a5, and a7) for amplitude
settings. These values are used for the microstep wave calculation. All amplitude values normally
should meet the condition a1 ›› a3 ›› a5 ›› a7 within the range 0.00… 1.00. The microstep wave
calculation is done via Fourier synthesis.
Please refer to the MOTOR DRIVER REGISTER of the TMC5031 datasheet.
Figure 6.17 Microstep wave dialogue with sin wave (default setting)
The formula in the expression evaluator can be changed to optimize motor performance. Have a look at
the following examples, please.