So I'm planning to use an ESP32 microcontroller as the brains of a new CNC machine running Grbl. The ESP32 uses 3.2 V logic on all pins. I happen to have several of the logic level shifters like in this picture and link:
Attachment 409788
Attachment 409790
https://www.sparkfun.com/products/12009
I plan to use them to convert the 3.3v logic to 5v like this picture. All of the devices on the right side of the last pic would use the same 5V source for signal power
I have a couple questions about them.
1. if used like the last picture, will they also provide isolation between the MCU and whatever is hooked on the right (Switches, motor drivers, prox sensors, etc) ?
2. If they will work for isolation I assume that the grounds should not be connected on the HV and LV sides, otherwise the isolation is at least somewhat defeated. Correct?
3. Some of the pins on the MCU don't have internal pull-up resistors, but it looks to me like adding these would take care of that anyway. Is this correct?
4. Would I be better off using optocouplers? I don't have any but could get some if they are a better option.
Thanks,
John B.