Is it possible to configure a SPORT to receive a variable length of data words? I'm thinking that the RX DMA could be set to some large number of values, and configured with LAFS-alternate so the Frame brackets the data. When the sender transmits the data, whether it's 10 words or 20 words, the end of Frame would trigger an IRQ and then the ISR could disable the SPORT and process the data. I'm not sure how to configure the Frame IRQ and the DMA at the same time.
This would be helpful in certain arrangements where different data packets are sent spontaneously.