Hi,
I am connecting a 2.0 Full-Speed peripheral to a system with an i.MX6Q, and there seems to be a protocol violation wherein the i.MX6Q is responding to a NAK on an OUT PID with PINGs. The USB 2.0 spec explicitly disallows the use of PINGs for Full-Speed devices. Attached are some oscilloscope screenshots showing the NAK and a PING, and you can see that the bus decoder on the scope does not decode the PING, as it should not ever be used at Full-Speed. The peripheral does not reply to these PINGs. After 3 PINGs, the peripheral power cycles itself.
I have checked the errata https://www.nxp.com/docs/en/errata/IMX6DQCE.pdf and not found anything addressing this issue. Am I correct in concluding that this is a protocol implementation error, or could something else be going on here?
Thanks,
Tim G
