topic Re: IMX7D USB_OTG_VBUS allowed enable power level? in i.MX Processors

IMX7D USB_OTG_VBUS allowed enable power level?

frankyhsu — Thu, 14 Dec 2017 03:29:13 GMT

Hi Support,

We are checking the property of this pin and we might need to use 3.3V instead of 5V from USB connector. What's the limitation? Is 3.3V of for it?

Re: IMX7D USB_OTG_VBUS allowed enable power level?

Yuri — Thu, 14 Dec 2017 04:04:02 GMT

Hello,

In order to meet specs, minimum VBUS is 4.75 V; maximum is 5.25V.

Generally, i.MX7 can work in device mode without VBUS, but it is needed to modify

software to disable VBUS detection.

But the following impacts should be taken in consideration:

1) i.MX7 may NOT detect plug in/out events, because the interrupt is triggered

by the VBUS level;

2) i.MX7 USB may NOT work at low power mode, because VBUS functions as the

wake-up source.

Have a great day,
Yuri

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Re: IMX7D USB_OTG_VBUS allowed enable power level?

frankyhsu — Thu, 14 Dec 2017 04:14:30 GMT

We see that the 3.3V input and even lower to 1.8V, it can still work

unless we connect nothing. So, NXP can still accept the 4.75 as the

minimum?

Franky Hsu

Sercomm Corp.

2F, No.3-1, YuanQu St., Nankang, Taipei 115, Taiwan

+886-2-26553988 #2552

寄件者: "Yuri" <admin@community.nxp.com>

收件者: "Franky Hsu" <franky_hsu@sercomm.com>,

日期: 2017/12/14 下午 12:04

主旨: Re: - Re: IMX7D USB_OTG_VBUS allowed enable power

level?

NXP Community

Re: IMX7D USB_OTG_VBUS allowed enable power level?

reply from Yuri Muhin in i.MX Community - View the full discussion

Hello,

In order to meet specs, minimum VBUS is 4.75 V; maximum is 5.25V.

Generally, i.MX7 can work in device mode without VBUS, but it is needed

to modify

software to disable VBUS detection.

But the following impacts should be taken in consideration:

1) i.MX7 may NOT detect plug in/out events, because the interrupt is

triggered

by the VBUS level;

2) i.MX7 USB may NOT work at low power mode, because VBUS functions as the

wake-up source.

Have a great day,

Yuri

Re: IMX7D USB_OTG_VBUS allowed enable power level?

Yuri — Thu, 14 Dec 2017 09:16:27 GMT

Hello,

You may use Your configuration - it does not violate (hardware) maximum ratings,

but do not forget about possible (software) impacts.

Regards,

Yuri.