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USB3 connection and D+/D- lines
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RSKV

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USB3 connection and D+/D- lines

Stas1967 posted on 15 Jan 2013 10:08 AM PST
Member
8 Forum Posts

I am usning USB3 connection only. Do I need connect D+ and D- line? If yes what is functionality of these lines in USB3 protocol.

Thank you

 

Re: USB3 connection and D+/D- lines

RSKV posted on 15 Jan 2013 07:25 PM PST
Cypress Employee
655 Forum Posts

Hi,

You need D+ and D- lines if you want to operate your device in USB2.0 speeds (High, Full and low speed).

Thanks,

sai krishna.

Re: USB3 connection and D+/D- lines

Stas1967 posted on 16 Jan 2013 10:07 PM PST
Member
8 Forum Posts

And if not? I want only superspeed. Somebody told me that USB agents need it for autonegotiation...

Re: USB3 connection and D+/D- lines

RSKV posted on 16 Jan 2013 12:58 AM PST
Cypress Employee
655 Forum Posts

Hi,

If you want only superspeed then you can leave D+ and D- open. There should not be any problem with the functionality of device under superspeed but it is not expected to pass USB certifications.

Thanks,

Sai Krishna.

 

Re: USB3 connection and D+/D- lines

Avishai posted on 16 Jan 2013 02:14 AM PST
Member
2 Forum Posts

 Hi,

 

I tried to mask the D+/D- pins, to simulate this issue, and did _not_ see the Cypress on the PC.

Please note that in our system configuration the boot is via USB, so the booter should loat the code on the USB3.

 

Does the booter support USB3 operation?

 

Thanks, 

  Avishai

Re: USB3 connection and D+/D- lines

RSKV posted on 16 Jan 2013 03:50 AM PST
Cypress Employee
655 Forum Posts

Hi,

That is the problem in your case. FX3 bootloader works in USB2.0 mode; not in USB3.0.

So it is not possible to leave out the D+ and D- lines if you are opting for USB boot.

Thanks,

sai krishna.



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