Table 149. Sdio I/O Definitions; Figure 327. Sdio Adapter - STMicroelectronics STM32F405 Reference Manual

RM0090
Pin
SDIO_CK
SDIO_CMD
SDIO_D[7:0]
31.3.1 SDIO adapter
Figure 327
The SDIO adapter is a multimedia/secure digital memory card bus master that provides an
interface to a multimedia card stack or to a secure digital memory card. It consists of five
subunits:
• Adapter register block
•
Control unit
• Command path
•
Data path
•
Data FIFO
Note: The adapter registers and FIFO use the APB2 bus clock domain (PCLK2). The control unit,
command path and data path use the SDIO adapter clock domain (SDIOCLK).
Adapter register block
The adapter register block contains all system registers. This block also generates the
signals that clear the static flags in the multimedia card. The clear signals are generated
when 1 is written into the corresponding bit location in the SDIO Clear register.

Table 149. SDIO I/O definitions

Direction
MultiMediaCard/SD/SDIO card clock. This pin is the clock from
Output
host to card.
MultiMediaCard/SD/SDIO card command. This pin is the
Bidirectional
bidirectional command/response signal.
MultiMediaCard/SD/SDIO card data. These pins are the
Bidirectional
bidirectional databus.
shows a simplified block diagram of an SDIO adapter.

Figure 327. SDIO adapter

DocID018909 Rev 11
Secure digital input/output interface (SDIO)
Description
1015/1731
1067