I tried to replicate the usb part of NUCLEO-F439ZI dev board to a project, without success.

[FabioVasconcelos]

I'm using vbus to power supply the MCU, through a voltage regulator.

For the MCU I'm using the stm32f427, not the 39, as in the development board, but they seemed compatible with my project features.

When I connect the board to my laptop via USB, the overcurrent led turns on, and my operating system (ubuntu) does not detect any new USB device.

If I connect boot0 to VCC, the command lsusb in ubuntu takes some seconds to respond.

Can you please give me some suggestions?

Thank you in advance

[MM..1]

Your J21 usb con is faultly connected, too USB data lines need wire as diferential pair on pcb.

[FabioVasconcelos]

Hello @MM..1​,

What do you mean by a faulty connection?

​

The data lines are differential, and according to kicad calculator they have ~100Ω (Hope is it not the cause).

I also have 5V in my voltage regulator, so it seems that the power lines are correct, then are connected according with the table below:

[MM..1]

GND pin is open

[FabioVasconcelos]

I figure that the overcurrent led turns on because of boot0 is connected to 3.3V, when I change boot0 to gnd, the led turns off. I will need it later, but for now, I will not take that for the equation.

I desolder the IC3 because you are right I will not need it, thank you. But stills not working, the PC does not detect the board.

Another thing that I realize is that programming by jtag through stlink v3, if I supply the board via USB, everything works fine and I flash the board without a problem, using an external 5V power supply, it's not programming. VUSB and external power supply go directly to a voltage regulator ( 5->3.3V) to supply everything. The only thing that changes is PA9 pin, which receives VUSB.

[MM..1]

Your board need firmware loaded for detect on PC. Isnt based on you pin connection.

And for use DFU detection is defined in AN2606 plus

[FabioVasconcelos]

Hello @MM..1​ 

I have PA11 and PA12 correctly connected, I hope but dfu is not working.

Maybe the first line means something? USB OTG FS configured in forced device. What does this mean?

My boot0 connection:

 

I really apreciate your effort. Thank you!

[MM..1]

Ok try this order

1. Unconnect all power and cables from your board
2. Cannect jumper BOOT0 high
3. Connect USB cable between PC USB 2 port and board with ok data cable
4. Power on your board
5. Check on PC device manager new device

On PC you need preinstall STMCubeProgrammer as step 0

If device isnt found check if syste is in bootloader , but detect other interface

or MCU fail other way.

[Chris1]

Is there actually nothing connected to the VCAP pins as it appears above?

That would be a problem...

[FabioVasconcelos]

Thank you, I will give it a try and let you know the result!

[Chris1]

[FabioVasconcelos]

I figured it out.

I'm missing a crystal in PH0 and PH1, not it's working!

Thank you all!