SDIO_CLK This pin provides
the clock to the SDIO card from the external SDIO host.
SDIO_CMD This pin is used for two-way communication between SDIO
peripheral and the host. The host transmits commands to the peripheral and the
SDIO peripheral drives responses to the commands on this pin.
SDIO_DAT[3:0] SDIO data
lines establish the crucial pathway for information exchange between host
systems and peripheral devices.
SDIO_OBI Depending on the
configuration of the host in the initialization, host interrupt is presented on
the data bus (IBI – in band interrupt) or on dedicated pin (OBI – out band
interrupt).