i.MX ProcessorsのトピックRe: USB 3 Polarity Inversion TX and RX

USB 3 Polarity Inversion TX and RX

MNTR — Thu, 04 May 2023 06:32:22 GMT

Hello,

according to the USB3 spec it is allowed to invert the polarity of the USB_TX or USB_RX signals without any further adjustments.

Since we got some issues with our USB-Interface where we inverted USB2_TX_N and USB2_TX_P as well as USB2_RX_N and USB2_RX_P, I want to make sure this is allowed with the i.MX8M Plus.

Can anybody confirm this inversion is possible and we do not have to adjust any settings or similar?

Re: USB 3 Polarity Inversion TX and RX

Dhruvit — Mon, 08 May 2023 09:43:32 GMT

Hi @MNTR,

I hope you are doing well.

TX/RX polarity inversion is supported on i.MX8MP.

USB 3.0 PHY has auto polarity detection and adjustment support.

Thanks & Regards,
Dhruvit Vasavada

Re: USB 3 Polarity Inversion TX and RX

MNTR — Tue, 09 May 2023 06:24:14 GMT

Hi @Dhruvit ,

thank you very much.
Are there any limitations?
For example: can I invert just one of the super speed pairs (TX inverted, RX not inverted)?

Thanks in advance

Re: USB 3 Polarity Inversion TX and RX

Dhruvit — Thu, 11 May 2023 11:09:42 GMT

Hi @MNTR,

I hope you are doing well.

i.MX8MP has Synopsys USB 3.0 PHY.

Lane Polarity inversion only talks about Rx signals.

Please refer to Universal Serial Bus 3.0 Specification for more information.

Thanks & Regards,
Dhruvit Vasavada