TUSB2046B USB hub is not working. Device is not recognized

Just to add on, the GND and SYS_GND are actually the same nets.

Hello,

You need to connect a 1.5K pull-up from DP0 to 3.3V.

Regards.

Hi Elias,

thanks for your prompt reply.

Just one question, do I need to swap DP0 and DM0 pin for upstream ports connected to mini USB type B port??

Regards

Sorry, I don't understand your question.

The DP0 terminal of the TUSB2046B should be connected to the D+ pin of the connector, you can't connect it to the D- pin.

Regards.

Hi Elias,

Noted, so can I conclude that DP0 of TUSB2046B should be connected to Pin 3 of a Mini USB Type B  connector??

regards,

Correct,

DP0 is connected to Pin#3 of the type B mini-connector.

Also, remember to connect the 1.5K pull-up on DP0.

Regards.

Hi Elias,

Thanks for your clarification. Actually, I already tried to place a 1.5kohm pull up resistor on DP0 pin. But, the USB hub is not recognized when I connected to my laptop.

Just one more question,

Will the TUSB2046B detected as a Generic USB hub, when it connected to a Windows 7 host??

I don't have anymore blank PCB boards as I have tried most of them. Will update the findings when another batch of new PCB arrived.

Regards

Yes, it will be show up as a Generic USB Hub, the below image show the hardware id it should have.

I've just seen that your power-on reset device DS1818 seems to have a fixed delay of 150ms, this is not good, the TUSB2046B must respond to the USB host within 100ms after power-up, the recommended power-up reset timing fo the hub is 1ms to 3ms. You can do this with a simple RC circuit or changing your supervisory device.

Regards.

Hi Elias,

The new PCBs have arrived. There're good news and bad news.

Good news is that my laptop is able to detect the USB hub. But the bad news is that it happened intermittently. Meaning that it is not consistent for the PC to detect the USB hub. I also tried on another PC, it is still having the same symptom. Some of the PC even worst, it can't recognized the USB device.

At first, I suspect it is the RC delay on the RESET pin, and hence I tried R with 2.2k and 1.5k, with 1uF Cap, but the result still the same.

Can you please advise??

Regards,

Is it the same schematic as the one at the first post?

Check the pull-up on DP+. Check the impedance on DP/DM lines, it should be 90ohm differential. Check the power rails and the oscillator.

Can you take a scope capture of the power-up sequence measuring VCC, RESET, XTAL ?

Is the SUSPEND output active when the hub is not recognized?

Regards.