this has really given me a good what for.
I seem to have some sort of a voltage transient or spike causing some weird behavior on this circuit.
I have an ignition signal and a tach signal (hooked to the positive and negative of an automotive ignition coil).
with the coil firing, the outputs on the left of the microcontroller can seem to flutter regardless of being called high or low.
what is really strange is that the controller doesnt seem to get slapped bad enough to cause it to act strange with its process (it still reads rpm clean, ignition input acts as expected, and analog inputs continue to read undistorted - just my stepper drive outputs seem to flutter on their own every once in awhile (even when in the code they are not being commanded to).
with the coil off, the stepper acts normal - and oddly enough both ignition and tach lead have to be removed from a running coil for the issue to not be present (id expect it on the tach side potentially, but the ignition lead surprised me).
things I have tried:
de-soldered the 470ohm resistor from that common ground lead, soldered on a wire to the end of it and put it right to the incoming NEG screw terminal on the board. issue was still present. (with ignition lead removed)
ignition lead does not cause an issue if not hooked to the coil NEG like if i wire it to the board voltage. same voltage source supplying the coil).
so im stumped - something is happening with the magnetic field collapsing in the coil to cause the issues with the current circuit, even though the circuits read and function clean, the stepper drive has weird ghost pulse behavior.
anyway, does anything jump out to anyone as being super obvious?
I seem to have some sort of a voltage transient or spike causing some weird behavior on this circuit.
I have an ignition signal and a tach signal (hooked to the positive and negative of an automotive ignition coil).
with the coil firing, the outputs on the left of the microcontroller can seem to flutter regardless of being called high or low.
what is really strange is that the controller doesnt seem to get slapped bad enough to cause it to act strange with its process (it still reads rpm clean, ignition input acts as expected, and analog inputs continue to read undistorted - just my stepper drive outputs seem to flutter on their own every once in awhile (even when in the code they are not being commanded to).
with the coil off, the stepper acts normal - and oddly enough both ignition and tach lead have to be removed from a running coil for the issue to not be present (id expect it on the tach side potentially, but the ignition lead surprised me).
things I have tried:
de-soldered the 470ohm resistor from that common ground lead, soldered on a wire to the end of it and put it right to the incoming NEG screw terminal on the board. issue was still present. (with ignition lead removed)
ignition lead does not cause an issue if not hooked to the coil NEG like if i wire it to the board voltage. same voltage source supplying the coil).
so im stumped - something is happening with the magnetic field collapsing in the coil to cause the issues with the current circuit, even though the circuits read and function clean, the stepper drive has weird ghost pulse behavior.
anyway, does anything jump out to anyone as being super obvious?
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