The SD card detect logic monitors the SD_CD# pin for card insertion/removal events. It implements debouncing logic to filter false transitions on the SD_CD# pin. The card insertion and removal events are reported to the SD host register set from which the interrupt is eventually generated.
This Figure shows the SDHC card detection.
•The SD host controller card detection uses the SD host control register card detect signal bit as the selection bit.
•If the SD control register card detection bit is 1'b1, then the card is inserted during boot time or an eMMC.
•If the SD control register card detection bit is 1'b0, then the SD slot interface is used to identify the insertion and removal of the card using the MIO pin.