I working on a project that uses 6 NEMA 8 stepper motors very similar to This One, each stepper will be driven by a DVR8834 and the STEP/DIR logic supplied by a ATmega328P which has a VCC = 2.7V to 5.5V and MAX current per I/O pin of 40mA (page 258 of the datasheet). My question is this can I tie all the STEP inputs of the DVR8834's to a single I/O pin of the ATmega328p to have all the motors step in unison? Am I missing something like drawing too much current on the I/O pin or "cross talk" of the DVR8834's?

Thanks in advance

  • \$\begingroup\$ You'd have to look up the input loading and consider things like wire runs and environment (even with only one). A buffer may be an option to make distinct "copies" of the signal. \$\endgroup\$ – Chris Stratton Mar 19 at 15:25

Looking at the datasheet, section 7.5 'Electrical Characteristics' under logic-level inputs, we can see that the highest current draw of those inputs (at 3.3V anyway) is only 20 µA. This means that even if we put 10 of these in parallel you would only be drawing 0.2 mA. This is well under the 40 mA that the ATmega328P can handle.

Because the IO can drive so much harder than the those inputs, I wouldn't worry too much about cross talk. This should work fine.


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