Hi
I've implemented the TUSB2036 but have come across a problem which I'm struggling to solve. PCB layout of
tracks have been length matched and routed as 90R differentials.
I have setup the TUSB2036 as 2 permanent connected devices and 1 external device, self-powered.
All the ports work very well when I connect a flash drive to them but I can't seem to interface with a PIC32 and
get a constant USB device not recognized message. Only the PIC32 in not protected by over-current.
I have disconected the PIC32 from the usb-hub by removing R54&R55 and soldering a usb connector directly to the PIC32 usb pins and it always registers as a open com port when I connect to my pc's usb port, so
I'm quite certain the code works. If I then take that USB wire and plug it into the TUSB2036 external port I still get the "USB not recognized message".
I have also tried to power the 5V Bus with an additional power supply but haven't seen a change.
The following is tests that I have done:
1. Plugged the upstream side of the usb-hub into the PC (Windows detects it as a generic hub controller)
2. Inserted a flash drive into external port 3 ( Windows recognizes flash drive and allows access)
3. Soldered a usb female to port 2 and inserted a flash drive ( Windows recognizes flash drive and allows access)
4. Desoldered R54&R55 and soldered a usb female to port 1 and inserted flash drive ( Windows recognizes flash drive and allows access)
5. Soldered usb-male cable to PIC32 side of USB D+ and D- and connected to PC (Displays recognized com port of PIC)
6. So this tells me both sides are working of port 1. Place R54&R55 back and get the "USB not recognized" message.
I have repeated these tests playing around with bus-powered 5V supply and self-powered option.
I've also tried to manually trigger the usb reset with a button, I can see the hub reset but then get the same "usb not recognized" message.
if I do the hub-reset with flash drive inserted it will re-initialize the flash drive and allow access.
I have seen in the datasheet that the usb hub reset is timing specific, not sure if it will make a difference if it's triggered by the PIC32 for the correct period.
Thank you.
Regards
Francois
