USB OTG with SSP1.2 or SSP1.3

 Hello everybody,

I am looking for more complete documentation than the user manual regarding USB in OTG mode for the S3A7.

My questions would be:

Is it necessary to use the 2 inputs OVERCURA and OVERCURB to detect a change on VBUS, or only one of these 2 inputs would suffice with the VBUS input?
What is EXICEN for? VBUSEN would not be enough?

If I can configure the BSP for USB OTG, is there a dedicated framework in the SSP? It does not seem like.

An Application note about this subject?

I have no experience in OTG ...

Thank you in advance for your help.