Hi everyone,
I have a state machine which creates the following INFO when synthesised using Xilinx ISE6.1.
INFO:Xst:1813 - Unable to extract FSM on signal : outputs depend on both state and next state.
Is this something I should be concerned about?
THanks
Not if state and next state are register outputs.
-- Mike Treseler
Oh ok. Next state is not a registered output. The state machine is a 2 process state machine ie the clocked process registers state from next state, and the next state process is a combinatorial process.
Can you help me to understand the problem and what has been synthesised?
Thanks
Consider posting (part of) your code. It's easier to see what you do and to explain what is going on.
Jan
if you have a combinational process like:
always @(state or [some control inputs] ) begin case (state) state1 : state = blablabla; endcase end
the synthesis tool will never extract a register you should sample the state in a separate process. post a part of your code, this would be more clear.
Vladislav
Consider using a single process.
-- Mike Treseler
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