Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/SiM3_NRND/SIM3C167_B/I2S_0/FIFOCONTROL#0x0
FIFO Control
Transmit FIFO Low Watermark.
Receive FIFO High Watermark.
Transmit FIFO Flush.
1 (SET): Flush the I2S transmitter FIFO.
Receive FIFO Flush.
1 (SET): Flush the I2S receiver FIFO.
https://github.com/cmsis-svd/cmsis-svd-data