I have to ask a question about this component (Dual MAX14870) which permits to control the PWM for two motors outputs. I succeeded to make work the card with two motors without trouble first.
When I disconnected the 3.3V from the Arduino (and all was again on: input source, arduino, …), a resistance on the card burned so the card is dead, and it is also the same for the Arduino which controlled the card. It seems when I disconnected all the power of the input source went through the Arduino.
I connected all the ground of the card (expected the GND next to the Vin for the input source) on the ground of the Arduino. Is it the good thing to do? Because for other component which does the same thing, it is precised that all the grounds on the card has to be on the same ground, and more precisely the ground of the input source of power.
Thank you in advance for your help. And sorry for my approximative english