TUSB2077A: PWRON outputs are always high.

Hi,

Can you repost the schematic?

Regards,

JMMN

5826.USB_HUB.pdf

I found out that hub must be connected to usb host (at start i tested it without connecting anything)
But now I have second question.
How i should connect hubs in cascade? Where pulldowns or pullups should be placed? I am guessing that on this connection between hubs, should be 15k pulldowns on D+ D- and 1,5k pull up on D+. Am I right?

Also i have this problem when i connect HUB to usb at PC(power form PC is not used, it can be seen at schematic i uploaded):

Hi Tomasz,

The 15K pulldowns should be on the downstream facing ports and the 1.5K pullup on DP should be on the upstream facing port.

Check to see if any of the overcurz inputs are low, I don't see anything on your board that would cause a short.  Check VBUS on the connector from the host to see if it is staying at 5V.

Regards,

JMMN

Every overcurrent pin (except those which are not used) are high. I think the problem is when hub is not configured (not connected to pc), when i connect hub to host all PWRON go low.

But still i have problem to connect hubs to usb host. When i connect usb to pc, pin HUBCFG go high for 3 seconds and then computer prompt the message i attached above(about power surge), then HUBCFG go low and SUSPND go high. I checked voltage on VBUS and it is 5V all time, even after error message. I have 3 PCB with 2 hubs each and every PCB behaves the same way. I tried this even in other laptop - same problem. The strange things is, 5V rail from USB host is not used, because BUSPWR is high. There is only TVS and i even desolder TVS so VBUS is attached only to usb connector. Maybe this description helps you to figure out what is going on.

I have one more question about HUBCFG. If usb hub works properly, then HUBCFG must be high? Datasheet metion only this:
"Hub configured. Used to control LED indicator. When the hub is configured, HUBCFG is high, which can be used to turn on a green LED. When the hub is not configured, HUBCFG is low, which can be used to turn on a red LED."
Does "configured" mean "working properly"?

P.S.: I also measured current drianed from usb host and its 0.

Hi,
Unused port were floating, so there was 0V on those pins. I do some soldering to pull-up OVERCUR pins, and after this changes all OVERCUR pins are 3,3V and there is no more error. I thought that hub which isnt in ganged mode has no problem with unused ports error but it sure has.

Thank you a lot.
Best regards,
Tomasz