Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Freescale Semiconductor/MK21D5WS/I2S0/RFR#0x0
SAI Receive FIFO Register
Read FIFO Pointer
no description available
Write FIFO Pointer
https://github.com/cmsis-svd/cmsis-svd-data