PROCESSOR-SDK-AM335X: USB ID pin

Eby Jayan

Expert 2115 points

Part Number: PROCESSOR-SDK-AM335X
Other Parts Discussed in Thread: AMIC110, AMIC120

HI,

We are using USB0 in our design based on AM335X.

While using the interface we had provided an external on the USB ID pin so that it works in Host mode ?

What should we do in case we have to use it as a Device and also in OTG mode .

From the Datasheet i Found that the ID oin max voltage is 2.1V ( 1.8V operational) .

In case of any external pull up required for the same, please confirm.

Regards

Eby

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

Hi,

You must NEVER apply external voltage to the AM335x USB ID pins. See this wiki for correct usage: processors.wiki.ti.com/.../AM335x_Schematic_Checklist

0 Eby Jayan over 7 years ago in reply to Biser Gatchev-XID

Expert 2115 points

HI Biser,
Thanks for the reply
so i understand that in peripheral mode the signal should not be even connected to the connector and if we use in the OTG mode then the Signal can be connected to the SB connector without any pull up/ down right ?

Regards
Eby

0 Biser Gatchev-XID over 7 years ago in reply to Eby Jayan

TI__Guru**** 393215 points

Correct.

0 Eby Jayan over 7 years ago in reply to Biser Gatchev-XID

Expert 2115 points

Thank you so much for the clarification

Regards
Eby Jayan

0 -DK- over 7 years ago in reply to Eby Jayan

TI__Mastermind 27890 points

Just chiming in to add a bit more detail to this given that it's a very popular question. The below is applicable to AM335x, AM43xx, AMIC110, and AMIC120; other processors may handle the USB_ID pin differently so always refer to the device specific TRM/Datasheet.

For 100% Host mode operation, the ID pin can be strapped directly to GND. No resistor is needed.

For 100% Device mode operation, the USB_ID pin should be left floating.

For OTG mode (actually these processors support DRD, or Dual-Role Device, rather than true OTG), the USB_ID pin should be connected directly to a USB MicroAB receptacle. No pull-up or pull-down. Direct connect.

By following these requirements, the state of the USB_ID pin is controlled exclusively by the USB device that is plugged into the receptacle. A USB Peripheral will leave the USB_ID pin floating while a USB Host adapter will ground the same pin; the processor's mode of USB operation can now be determined by the state of the USB_ID pin.

0 Eby Jayan over 7 years ago in reply to -DK-

Expert 2115 points

Thank you so much for this information

Regards

Eby

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PROCESSOR-SDK-AM335X: USB ID pin