modeling connecting Processor with memory

[Pasacco]

dear

I implemented simple processor (actually simple FSM) -
- Input port: clock, reset, data_in
- Output prot: enable(memory enable), rw(read/write), address, data_out

And consider Memory (Xilinx BRAM) -
- Input port: EN, CLK, DI, RESET, WE, ADDR
- Output port: DO

Then I directly connected the processor with Memory, as follows.
- processor to Memory : enable => EN, rw => we, address => ADDR,
data_out => DI,
- memory to processor : DO => data_in
- clock and reset are all the same

Problem is that

Processor is working fine when the FSM (processor) is written as the
following.

---------------------------
architecture
begin
process(reset,clock)
begin
if reset='1' then
CS<=Init; -- current state
elsif clock'event and clock='1' then -- rising edge
NS<=CS; -- next state
end if;
end process;

process(ES,en,ab,Ra,Rb,cntA,cntB)
begin
case ES is
when Init =>
if a='0' then NS <= READ_MEM1;
end if;
when READ_MEM1 =>
if b='1' then NS <= READ_MEM2;
end if;
.....
end case;
end process;