An interface system includes a secure digital (SD) driver module to communicate with an SD card over a bus, a secure digital input/output (SDIO) driver module to communicate with an SDIO card over the bus, and an input/output port. A method of operating a host in the interface system includes coupling the bus to the SD card while a first mode is enabled, coupling the bus to the SDIO card while a second mode is enabled, and enabling the first mode in response to a request for access to the SD card. The method includes, while the first mode is enabled, (i) listening for a notification signal arriving from the SDIO card via the input/output port, indicating that an interrupt is pending at the SDIO card, and (ii) in response to the notification signal, enabling the second mode to allow the SDIO card to transmit the interrupt to the host.