CTL_STATUS_t ctl_ms_sd_spi_read_scr(CTL_MS_SD_DRIVER_t *driver, unsigned char *scr);
ctl_ms_sd_spi_read_scr reads the system control register (SCR) from the media card into scr using the device driver driver. scr must point to a buffer that is at least 8 bytes in size.
ctl_ms_sd_spi_read_scr is thread-safe.