SCB UART interrupt

I'm a psoc beginner and I'm trying to set an interrupt on FIFO is not empty.

I'm recieving a RS-485 serial stream from an external board that sends data every 3 seconds or so. The signal is low between data update. I have confirmed that I am receiving the information correctly.

The problem I'm faced with is the interrupt being continuously fired. I believe this is due to the RX FIFO accepting NULL between data being sent from the external board, which means the RX FIFO is always not empty.

Is this proper behavior for the SCB UART? Is there a way to ignore incoming NULL characters? I expected it to be blocking until a non NULL character was received.

I tried to search the forums but didn't find what I was looking for. First time posting, Any help would be hugely appreciated!

Thanks!