Atom Lite only powers via USB-C but not 5V from pin header
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I got the Atom RS485 kit and my RS485 endpoint provides +12V DC on the orange header which I want to use to power the Atom.
I measure +13V at the DC12V input pin. Without the Atom Lite connected, I measure 4.84V at the 5V pin header on the base.
However, when I connect both, I cannot reach the Atom. Note that even with the Atom Lite in place, I still measure a fixed +13V at the DC12V input pin, hence I do not believe the source is unable to supply sufficient current (otherwise the voltage would drop).
However, if I power the Atom Lite via USB-C instead, everything works.
I thought already the base is broken, hence I ordered an additional base but unfortunately same.
Why does the Atom Lite fail to power from the 5V from the pin header?
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Hello @expjwt
according to the description the M5Atom can be powered from the 12 V.
A DC/DC voltage regulator chip is integrated in the ATOM RS-485, which can directly convert the 12V voltage of RS485 to 5V to supply power for M5ATOM, avoiding the trouble of using a separate power supply.
BTW: The 5 V on the header pin is connected to the 5 V on the Groove port. What voltage do you measure between 5 V and GND on the Groove port?
Thanks
Felix
