Hi, I'm having an issue with a Chinese A4988 clone connected to an Arduino Nano ESP32 (ABX00083, 3.3V logic).
The wiring follows the manufacturer's diagram, all voltages look correct, and I confirmed with an oscilloscope that the ESP32 is actually sending pulses to the STEP pin — yet the driver doesn't respond and behaves as if it's in sleep mode.
Out of desperation I rewired everything to an old Arduino Nano (ATmega328P, 5V logic) and the motor worked perfectly on the first try.
The original Allegro A4988 datasheet lists VDD from 3V to 5.5V, so 3.3V should be fine in theory. My suspicion is that the clone uses a different chip (HR4988 or similar) with a higher logic threshold — meaning the STEP/DIR/EN inputs aren't being recognized as HIGH at 3.3V.
Has anyone run into this? Is the only fix to level-shift the signals up to 5V, or is there something else worth trying first
Have you tried manually (with a wire) connecting the STEP and other pins directly to 3.3V and GND in turn to see if the motor steps?
If you are powering the driver with 3.3V, then 3.3V signals should work fine. Shifting the signals up to 5V when the driver is powered by 3.3V would damage the driver.
If you are powering the driver at 5V then 3.3V may not work, clone or original. You can use various chips from 74hct range to shift the signals to 5V. Most 74hc range are not guaranteed to work, with a few exceptions such as 74hc14 (Schmitt trigger inputs).
Yes, that sounds very plausible. Many A4988 “compatible” clone modules don’t always behave exactly like the original Allegro part, and 3.3V STEP/DIR signals may be marginal if the input thresholds are higher.
Before changing too much, I’d check these points:
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VDD on the A4988 logic side is actually 3.3V or 5V?
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RESET and SLEEP are tied HIGH.
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ENABLE is not accidentally held active/inactive the wrong way.
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STEP pulse width is long enough for the driver.
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Grounds between the Nano ESP32, driver logic, and motor supply are common.
If all of that is correct and the same setup works immediately with a 5V Nano, then using a simple level shifter or 74HCT buffer for STEP/DIR/ENABLE is probably the cleanest fix.
I would not assume all clone A4988 boards are reliable at 3.3V logic, even if the original datasheet suggests it should work. Similar Project, might help: Arduino Nano and A4988 Stepper Motor Controller - Share Project - PCBWay
Why not?
Then there would also be no reason to assume they would work reliably at 5V either.
That's not my point that the clone is necessarily unreliable at 5V, but we don't always know whether the clone actually matches the original Allegro A4988 specifications. Clones have stupid variations, that could give headaches.
Since the setup works with the 5V Nano and not with the 3.3V Nano ESP32, it suggests that the logic-level margin may be different from the original datasheet.
The actual HIGH threshold on the STEP and DIR inputs of that particular module. That would quickly confirm whether 3.3V logic compatibility is the issue or should be looking elsewhere.
True, so there is also no reason to assume it would reliably work at 5V or any voltage between 3V and 5V
Thank you all for answers it really helped. The solution i have chose is to order orginal drv8825 because datasheet says it can work with lower Vdd from 2.5 V up to 5.5 V so its better backp. Actualy i dont want to use level shifter because i have limited place on my PCB. So again thank you all i think issue is solved
Why would you believe the drv8825 datasheet and not the A4988 datasheet. I think before you waste your money on more drivers, you should find the real reason why it does not work and not assume that clones have "stupid variations" whatever that means.
The thresholds are a function of the operating voltage so the fact that the drv8825 can work at a lower voltage does not mean that the thresholds at 3.3V will be different.
So if you have a problem with the A4988 may may well still have the same problem with the drv8825