Hi @sowmiya_a,
SDXC standard supports a capacity greater than 32 GB up to 2TB, and the i.MX6SX datasheet mentions that it can support SDXC. So, the processor shall support up to 2TB.
In addition to this, the file system format supported in SDXC is exFAT, so the processor shall support exFAT as well.
One can refer to the below link for reference:
https://www.sdcard.org/developers/sd-standard-overview/capacity-sd-sdhc-sdxc-sduc/
Thanks & Regards,
Ritesh M Patel