I have designed in the i.MX6 Solo Lite in my board. I need to run SI sims on the USB traces. I have downloaded the IBIS file, mx6sl_416mapbga13x13_autmtv, from Freescale. I don't think the IBIS file implements a model for the USB pins. It looks like the models for the USB D+/D- pins are listed as "NC". Am I reading that correct?