I am having problems using an L298N module from eBay, sometimes called Qunqi L298N Motor Drive Board Module (The L298N H-bridge motor controller module - basics - YouTube). The driver program is the example code stepper_oneRevolution came with the Arduino kit. So I unhooked the motor and looked at the waveforms on the four pins where the motor used to be attached.
I found that the waveform on the pin #2 is always flat while the other 3 pins have square waves as expected. I thought I fried the board and order a couple of new ones, likely from a different vendor. When I got them, however, I found both of them also have the same flat line waveform on pin #2.
If I reverse the order of input pins “in1,in2,in3,in4” to “in4,in3,in2,in1”, then pin #3 shows zero volts. Also, I checked the input signals from Arduino pins 8,9,10,11. They all showed square waveform.
Is this by design? I thought one needs four square waves to drive a stepper motor.