Unused USB_OTG_2 interface ID and VBUS pins in IMX7

[logeshs]

Hi,

In MCIMX7D7DVK10SC, We are using USB_OTG2_ DP and USB_OTG2_DN for on board chip to chip interface. In this USB_OTG2 port VBUS and ID pins are not used.

Is there any special termination recommendation in the above case where DP, DN are used and VBUS and ID pin were unused. If there is any kindly suggest us the suitable termination. As of now it is left floating in the board without any terminations.

Thanks & Regards,

Logesh

[igorpadykov]

Hi Logesh

both signals can be left unconnected if not used.

Best regards
igor
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[logeshs]

Hi Igor,

We have received our Assembled Board. In our board USB_OTG1_DP/DN is connected to Micro USB connector. USB_OTG1_VBUS pin is left floating in processor.

Initially, We attempted to boot our board, by connecting USB cable from Test PC to device, but the device is not detected. But later we connected VBUS of connector and USB_OTG1_VBUS and device got detected and we are able to get prompt now.

But, We are using USB_OTG2_ DP and USB_OTG2_DN for on board chip to chip interface between IMX7D and LTE chip. In this port USB_OTG2_VBUS is left floating and not connected to VBUS pin of LTE. (But VBUS of LTE is supplied with onboard 5V.) For communication between IMX7D and LTE,

1. Does USB_OTG2_VBUS need to be powered for proper communication?

2. We did not Fan out USB_OTG2_VBUS in layout (floating). Do we have any internal register option to power up the USB_OTG2_VBUS pin?

3. Do we need to connect both VBUS of LTE and USB_OTG2_VBUS of IMX7D for proper communication?

Earlier as per above suggestion VBUS pins are not connected in USB_OTG2 port.

Kindly request you to provide the solution as soon as possible.

Thanks & Regards,

Logesh

[logeshs]

Hi Igor,

Thank you so much for your prompt reply.

In the same device, in USB_OTG1 is used for diagnostics purpose connected to microUSB connector. We are going to use the same USB connector for charging our wearable device. Shall we connect the USB_OTG1_VBUS pin to VBUS pin of USB connector or shall we leave it floating?

In other words, are we still able to use USB_OTG1 to access IMX7 for diagnostics purpose even if we left VBUS of IMX7 floating? (connecting only DP and DN from connector to USB_OTG1 port of IMX7)

Thanks & Regards,

Logesh

[igorpadykov]

Hi Logesh

there are two USB_OTG1_VBUS and USB_OTG2_VBUS 

Best regards
igor

[logeshs]

Yes Igor, I'm using Port 1 for Diagnostics and Port 2 for chip to chip interface. But port 1 is connected to USB connector, the same USB connector is used for charging, so shall i connect VBUS pin from USB connector to USB_OTG1_VBUS or shall i leave USB_OTG1_VBUS pin floating.

Thanks,

Logesh

[igorpadykov]

Hi Logesh

for charger questions suggest to create new thread.

Best regards
igor