I am trying to use USB stack 1.4.0 on KL26 mounted in our board. I have a problem concerning USB OTG peripheral .
I can't understand compeltely how the peripheral works.
First of all in KL26 RM (section 35.4.7), for the OTG STAT register (USB0_OTGSTAT), it’s stated that it “Displays the actual value from the external comparator outputs of the ID pin and VBUS” , which comparator is referring to ?
It seems that the USB ID signal has to be fed into a comparator for ID detection by USB peripheral. Can you explain in more details which comparator is here meant ?
Moreover is that register a read-only one ?
Again regarding the USB ID detection, in section 35.4.5, regarding OTG Interrupt Status register description, it is stated that the USB controller can generate an interrupt when it detects that ID signal change. I can’t find such an input in the OTG peripheral as described in the reference manual.
Thanks you very much!