topic Re: Difference between the two USB ID pins? in i.MX Processors

Difference between the two USB ID pins?

adevries — Fri, 30 Aug 2019 00:17:32 GMT

Hello,

I'm planning to use 8M Mini's USB ports in OTG mode. I saw that both USB ports have 2 ID pins. For USB1, it is signal usb_id, located on pad USB1_ID [D22] and usb_otg_id, located on pad GPIO_IO10 [AD10]. Are these ID pins redundant? Or do they accomplish different things? Just trying to figure out if I need route one or both to the USB connector.

Thanks

Re: Difference between the two USB ID pins?

Rita_Wang — Fri, 30 Aug 2019 09:23:54 GMT

The two pin function are the same. Here if you use the usb in OTG Mode you can refer to our i.MX6 series board reference design. You can use the usb1_id, and you also can use the usb1_otg_id. If you are using the usb1_otg_id, you'd better use the usb1_id the same with the usb1_otg_id.

Re: Difference between the two USB ID pins?

adevries — Fri, 30 Aug 2019 16:14:22 GMT

Hi Rita,

Thanks for the information. I'm a little confused by your last sentence, "If you are using the usb1_otg_id, you'd better use the usb1_id the same with the usb1_otg_id". Does that mean if I am using signal usb_otg_id (on pin AD10), then I must also use usb1_id (on pin D22)?

Thanks

Re: Difference between the two USB ID pins?

Rita_Wang — Mon, 02 Sep 2019 03:13:51 GMT

Yes, and you need to pull up the usb1_id pin.

Re: Difference between the two USB ID pins?

adevries — Tue, 03 Sep 2019 18:08:12 GMT

Hi Rita,

I'm still confused by this. Are you saying that I can use pin D22 to sense the USB ID signal, or I can use pin AD10 and pin D22 shorted together to sense the USB ID signal? Why couldn't I use pin AD10 by itself?

Also, can I use the internal pull-up resistors to pull the USB ID signal high?

Thanks