I'm not sure what you are asking, but assuming you want to see the resulting speed waveform after programming a trapezoidal speed profile...
You may be able to capture the drive signal and process it to show the trapezoidal waveform. If the drive signal is PWM a low pass filter might recover the trapezoid.
Another way to do this is to connect an analog speed sensor to the motor and view its output on the scope.
A small DC motor can be used as a generator - turning it into a crude analog speed sensor - you just need to couple the sensor motor shaft to the motor-under-test.
