Question: What will happen if we have a tri-state output connected to the input of the FIFO? We are always driving the clock and control inputs; it is only the data inputs that will be receiving a tri-stated floating signal.
Answer: In order to ensure that your FIFO does not receive floating signals as inputs, you can use the write enable (WEN) signal that is available on synchronous FIFOs to control the data being written to the FIFO.
When there is active data being driven onto the inputs, enable WEN. If the signal is tri-stated, disable WEN. This will prevent erroneous data from being written into the FIFO.
