There are two boards: stm32f407 Discovery and stm32f767 Nucleo. Both have 2 connectors: 1 for firmware via ST Link, the second USB OTG, for the MK to operate as a USB device. The problem is this: the boards do not take power directly from the USB OTG when connected via a wire to the computer and, accordingly, do not turn on. To turn on, you have to start the power in another way I spend all initialization in CubeMX. So the question is this: I have both broken boards, I did wrong initialization in cubemx, if so, what should I pay attention to, or is it the norm that you need some more power to start? Thank you in advance.

    1 answer 1

    This is a feature of these devices. They should take power only from the main USB-connector through which they are stitched. If you combine the power supply of these two USB-connectors, an error may occur on the host.

    Here is a fragment of the stm32f407 Discovery circuit concept. Here is the main USB connector of the programmer:

    enter image description here

    Here is the OTG USB connector:

    enter image description here

    As you can see, their food chains are not combined. This is done because no OTG assumes the functioning of the board in both USB Device mode, where it receives power from an external device, and USB Host ， in which the Discovery card itself must provide voltage to connect USB devices.

    • Thank you very much for your answer. Then there is another question, is it possible to gut a USB cable and get +5 V and GND to the board, and + D and -D to usb otg connector to run from one wire? - Nowsan
    • @Nowsan, if the programmer does not connect, then you can. Only better nn gutting the cable, and throw a jumper between the 5th programmer connector and the 5th OTG connector. - maestro