2 question while await my core 2, power and pinouts

wadoadi

Hi,
after returning a faulty M5Stack grey I ordered an M5Stack core 2, it's due next week!

I'm designing my own board for it and have the following questions:

is the stackable header the same pinout on all of the core range?
I don't want or need the internal battery instead I need to power from 12v so if I add a power regulator do I connect it to the 5V pin on the header? or I could build it to provide 3.3V and connect it to that pin! so I guess my question is how best to externally power an M5Stack via the header?
lastly, if powered via the 5V header pin will it switch on and off with the power?

felmue

No, the M5 Bus is slightly different for M5Core2. I've made a comparison sheet.
Yes, that is how I power one of my M5Core2 - via 5V pin.
But you'll need to modify the M5Core2 library code as currently it turns off the 5V input shortly after boot. The function call in question is: SetBusPowerMode(0); - which needs to be modified to SetBusPowerMode(1);. You also need a fixed version of SetBusPowerMode() - see here.
I haven't tried, but I don't think powering from 3.3V is possible - according to the M5Core schematic there are multiple 3.3V power lines inside the M5Core2 and the one connected to the M5 Bus, MCU_VDD, only powers ESP32, flash, RAM, etc., but for instance not the LCD which is powered through PERI_VDD.
Yes, but only if the battery has been removed.

Cheers
Felix

wadoadi

@felmue Wow thank you for all the information