SWCU192 November 2021 CC1312R7 , CC1352P7 , CC2652P7 , CC2652R7
The sample word length in memory (16 or 24 bits) is configured independently of sample word length on the serial interface (8 to 24 bits). Sample words are truncated when the destination is shorter than the source and zero-padded when the destination is longer than the source.
The I2S:AIFFMTCFG.MEM_LEN_24 field configures whether sample words in memory are 16 bit or 24 bit: