OSD335x-BAS USB questions

[Sisko]

We’re currently designign a OSD335x-BAS-based board where only USB0 is used as device-USB. Here two questions came up:

– can I leave all the seven USB1_xxx-pins open or do some of them need to be pulled to a specific level?

– how about USB0_VBUS – where connect it to? Directly to 5V input of the USB connector?

Thanks 🙂

[Erik Welsh]

We would recommend that you refer to the OSD335x Design Tutorial Application Note.  Specifically, there is a section on USB:

https://octavosystems.com/app_notes/osd335x-design-tutorial/osd335x-lesson-2-minimal-linux-boot/osd335x-lesson-2-usb-circuitry/

Please let us know if you have any additional questions.

 

 

[Sisko]

Hello Eirk,

thank yo ufor your feedback. These pages perfectly describe how to configure the USB-interface when it has to be used. But my question is what to do with the USB-pins when the related USB-port will NOT be used! Can I simply leave the related pins open or is it recommended to set them to some specific levels?

Thank you

[Erik Welsh]

Thanks for pointing out that the application note does not address how to connect the pins when not in use.  We’ll make sure to update the application note in the future.

To answer your question, when not in use:

• USBx_DM, USBx_DP, USBx_ID, and USBx_VBUS may be connected to ground or left floating
• USBx_CE should be left floating
• USBx_DRVVBUS may be left floating or may be used for the alternate GPIO function (see Table 4-2 in the AM3358 datasheet for more information)

Please let us know if you have any additional questions.

[Sisko]

Great, thank you!

[Author]

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