Memory Controller and State Machine

Hallo, I'm trying to create a memory controller based on a state machine to send to Microbalze signals like ram_data_out, read_acknowledge, write_acknowledge, etc...

I have connected it to OPB Bus.

My trouble is that I don't have a clear idea of the steps to read, write, read_acknowledge, write_acknowledge, etc...

In example: when microblaze must read data:

States:

0 -> 1) enable RAM 1 -> 2) assign address that comes from bus to ram address and assign ram_data_out to bus_data 2 -> 3) read_acknowledge = 1 3 -> 0) disable ram

Is it correct?

Where I could find a good documentation about it?

Many Thanks Marco