Using ESP32 SDIO like SD card

[Ra3wum]

Can SDIO slave block emulate SD card with file system like fat32?

[ESP_igrr]

Unfortunately, no. ESP32 SDIO slave supports only specific set of commands, such as IO read and write (CMD52, CMD53 in SD standard). SD cards need to implement a different set of commands, such as CMD17, 18, 24, 25 (single/multiple block read/write).

Since the commands are implemented by SDIO slave hardware, implementing the missing commands in software is not possible, unfortunately.