Pahub error with CORE2 with GoPlus2

  • I have a PAHub not connected error if I use a GOPLUS2 with my CORE2. The Pahub works perfectly, then if I add the GOPLUS2, I have a Pahub not connected error.
    I tried to change the I2C address to 0X71 or 0X75 without success ...0_1612029359667_IMG_5732.JPG

  • Hello @Arno

    I don't have a GoPlus2, so my assumption might be incorrect.

    That said, looking at the GoPlus2 schematics there is an MBus pin used for IR_OUT. On M5Stack devices that pin is GPIO5, however on M5Core2 that pin is GPIO33 which on M5Core2 is also used as PA_SCL. The I2C bus operates with pull-up resistors on SDA and SCL lines, but the IR_OUT circuit in GoPlus2 has a pull-down resistor on GPIO33. My guess is that the IR_OUT circuit interferes with the I2C operation.

    For reference: M5Stack bus vs M5Core2 bus GPIOs


  • @felmue
    Excellent analysis.
    I am surprised that there is not a compatibility table between the modules and CORE as well as the modules between them!

    Have any idea how to connect CORE 2 :

    • GOPLUS2
    • 2 x TOF UNITS
    • AMmeter UNITS
    • Voltmeter UNITS
    • Relay UNITS
    • NeoPixel

    Thank you in advance for all the help you gave in this forum

  • Hello @Arno

    you are welcome.

    If my analysis indeed is correct and IR_OUT in GOPLUS2 is the reason I2C stops working properly on port A, then for the units you'd like to connect to the M5Core2, I personally would modify the GOPLUS2 and cut the trace from GPIO33 to the IR_OUT. With that one modification you'd regain the functionality of port A. Then with the help of the PaHub this should cover the TOFs, Ultrasonics, AMmeter and Voltmeter units. I assume the Relay unit can be connected to the GOPLUS2. The NeoPixel I don't really know. The battery bottom for M5Core2 uses GPIO25 for that, so I guess that would work. How to connect to GPIO25 w/o soldering I have no idea.

    Option 2: use an M5Stack device instead of the M5Core2

    Option 3: find another GPIO that is free and can be used in place of GPIO33. However without electrical modification I don't see how the units could still simply be plugged into existing ports.

    Option 4: Modify M5Core2 port A to use GPIO21 and GPIO22 (same as M5Stack devices do).

    Option 5: wait and hope that M5Stack will release an updated GOPLUS2 module which works with M5Core2 out of the box.


  • I took your advice # 1 by turning off IR OUT and it works wonderfully. thank you again for your help, it allows me to progress quickly.

  • Hello @Arno

    nice! Thank you for the feedback. I am glad to hear it works now.

    @Zontex @m5stack :
    Maybe it would make sense to add a note in the GoPlus2 description about the incompatibility with M5Core2?
    And if not happened already maybe think about a modified GoPlus2 version where the GPIO for IR_OUT can be chosen through a dip switch to allow it to work with M5Stack and M5Core2 devices?