Hi there,

It seems like these days all my problems resolve around USB. Lucky me right?

I designed a PCB which has a FE1.1s cheap ebay USB host controller. The problem is that this IC is only recognised when it connected with another bus powered hub. When connected directly to the PC is gives device not recognised.
The fe1.1s is powered by a 5v 5a psu which get switched on when it sees the 5v coming from the pc.
I kept the traces really short and tried to follow the guidelines for the 90ohm differential impedance.
I was hoping that someone has a bit of experience in this field and if they could steer me in the right direction on how to solve this problem.

Kind regards,
Vytas

 

Is this the one you talkign about ! https://cdn-shop.adafruit.com/product-files/2991/FE1.1s+Data+Sheet+(Rev.+1.0).pdf

 

Yes that's the one and it seems to be working just fine when connected with the additional hub.
There is an ftdi chip and usb drive on it that then also work as intended.

 

Can you post a schematic? I'm not a USB pro, but there is some power negotiation that happens over USB. Do both your powered hub and your PC port support USB 3? If they are different then that's a hint. Did you use any protection ICs in your design? If yes, double check the wiring. We had a case where someone wired a protection IC incorrectly for and our USB chip would only work from a USB hub that allowed us to turn the power off to the USB port (the PCB had additional power source).

 

I've got a few USB devices I built out of PIC controllers. The wiring is not critical, as I used wire wrap wire and some other nasty tricks too.

Did you remember the pullup resistors?

"A USB device must indicate its speed by pulling either the D+ or D- line high to 3.3 volts. A full speed device, pictured below will use a pull up resistor attached to D+ to specify itself as a full speed device. These pull up resistors at the device end will also be used by the host or hub to detect the presence of a device connected to its port. Without a pull up resistor, USB assumes there is nothing connected to the bus. Some devices have this resistor built into its silicon, which can be turned on and off under firmware control, others require an external resistor."

 

Sorry for the late reply. I hadn't had the opportunity to get the schematic and pcb view of the circuit over the weekend and I didn't want to post without including them.

I've got a few USB devices I built out of PIC controllers. The wiring is not critical, as I used wire wrap wire and some other nasty tricks too.

Did you remember the pullup resistors?

"A USB device must indicate its speed by pulling either the D+ or D- line high to 3.3 volts. A full speed device, pictured below will use a pull up resistor attached to D+ to specify itself as a full speed device. These pull up resistors at the device end will also be used by the host or hub to detect the presence of a device connected to its port. Without a pull up resistor, USB assumes there is nothing connected to the bus. Some devices have this resistor built into its silicon, which can be turned on and off under firmware control, others require an external resistor."

The pullup resistors are integrated in the FE1.1S usb host controller. Atleast that is mentioned in the datasheet.

Can you post a schematic? I'm not a USB pro, but there is some power negotiation that happens over USB. Do both your powered hub and your PC port support USB 3? If they are different then that's a hint. Did you use any protection ICs in your design? If yes, double check the wiring. We had a case where someone wired a protection IC incorrectly for and our USB chip would only work from a USB hub that allowed us to turn the power off to the USB port (the PCB had additional power source).

The powered hub (My design) is USB2.0. My PC supports USB3.0 and I've tried connecting to both the USB 2.0 and 3.0 ports.

Here is the schematic and the PCB view of the circuit. Hopefully someone can shed some light onto this problem.

 

I think I have found the problem.

Adding a 1.8k resistor from the PC 5V to the D+ line seems to make the hub be recognised by the PC even with a direct connection. I still don't know why the FE1.1s pullup resistor isn't adequate. Atleast the device seems to be in good working order now.

Thanks.