There is a lot of information about the L293D on LMR and the web. But somehow I'm still unsecure if this circuit makes it possible to drive the stepper motor with only two control cables from the microcontroller to the L293D.
The stepper motor I use is the 28BYJ-48. With this stepper motor you need to make the following wiring:
After I have soldered four drivers I found that only two of them run fine. Two others not. One shivers the stepper. One does nothing.
While I was certain that it is my fault due to a solder failure (that I have not found) or a damaged H-bridge (that I have changed but got the same results) the LMR mogul pointed out that there might be indeed a conceptual problem with the circuit that is shown above (not the one from maxhirez).
So here is our shoutbox conversation (read from bottom to top, bottom is oldest, top is newest):
"Drivers are enabled in pairs, with drivers 1 and 2 enabled by 1,2EN and drivers 3 and 4 enabled by 3,4EN. When an enable input is high, the associated drivers are enabled and their outputs are active and in phase with their inputs. When the enable input is low, those drivers are disabled and their outputs are off and in the high-impedance state. With the proper data inputs, each pair of drivers forms a full-H (or bridge) reversible drive suitable for solenoid or motor applications."
Here is the conversation from the shoutbox:
merser: perhaps you should connect a dc motor to the circuit the way I have to see what I mean about the continual drive with en tied
I looked at the “Further Reading” on your actual machine post. You show an image from the datasheet on your stepper motors. Your stepper motor wires are numbered differently from the page I linked to above. Pink and Orange will be either 1 and 2 or 3 and 4. Yellow and Blue will be 3 and 4 or 1 and 2 in that order.