with the stm32f4 discovery board, i can get this running:
power the core with 5V switching power supply - by simple disconnecting the +- pins off the usb connector and solder the external power directly to the Wcore-pins where once the Breakoutboard was connected
the device is regocnized as usb-device on my computer, and everything is fine
(i need this extra power because using a lot off oled screens…)
with booth wcores (i use 2… how ever) this dont work.
i dont solder the +-wires coming from the usb-breakoutboard to the core, instead, i solder on the +-pins my external supply (so there is no connection to +- to the breakoutboard, but connection to the +- to the wcore….)
What i already tryed:
Wire a 4K7 or a 1K2 resistor between +- off the breakoutboard (i thougt the computer need some load, to recognize the deive/not going to sleep)
removed all parts, and Traces to USB-Host-Connector, Gate-Out and stuff.
removed the “ID” wire
make different powering up variants: 1. connect usb then powering up. 2. powering up then connect USB
…do the things above with and without ESD-protection diode (TVS1)
strange that it works with my discovery core boards, but not with wcore, since i dont have the shematics, i must ask at the forum. what is the difference between them in the power or USB-section? How get this running, where to hardwarehack.
thx for advice
