I have some doubts related to the relationship between PSEL and PENABLE signals in the APB Protocol. The specification informs that:
The PENABLE signal is asserted the following clock after PSEL is asserted and de-asserted after a transfer takes place.
I would like to understand about the following conditions:
1) Can PENABLE toggle while PSEL is de-asserted?
2) Can PENABLE be asserted in the IDLE and/or SETUP phase?
3) Can PSEL go log in to the SETUP phase?
4) What happens when PSEL is asserted high in the ACCESS phase and PENABLE is not de-asserted?