Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Microchip Technology/ATSAME51J19A/SDHC0/BGCR_EMMC_MODE#0x0
STPBGR=TRANSFER, CONTR=GO_ON
Block Gap Control
Stop at Block Gap Request
0 (TRANSFER): Transfer
1 (STOP): Stop
Continue Request
0 (GO_ON): Not affected
1 (RESTART): Restart
https://github.com/cmsis-svd/cmsis-svd-data