There are two SD/eMMC controllers on the Versal ACAP. The SD/eMMC controllers can be used for SD or eMMC and are mutually exclusive. When the controller is selected to support SD, the eMMC mode cannot be used.
The SD/eMMC controllers support three SD boot modes with different MIO pin usage. The SD1 (2.0) boot mode supports the SD2.0 specification. The SD1 (3.0) and SD0 (3.0) boot modes support the SD3.0 specification with an external SD3.0 compliant voltage-level shifter. In the SD boot modes, the RCU BootROM runs at an SD device clock frequency between 8.7 MHz and 19.3 MHz dependent on the REF_CLK setting. FAT 16/32 file systems are supported for reading the boot images.
The image search limit for SD boot mode is listed in Table 3.
For additional information on the SD/eMMC v4.51 controller, see SD v4.51 Controller.