Device
mmci_clk
mmci_cmd
mmci_dat[7:0]
8
MMC/SD/SDIOi
host controller
MMC card
or
SD card
or
SDIO card
CLK
CMD
DAT[7:0]
mmchs-002
Public Version
www.ti.com
MMC/SD/SDIO Environment
24.2 MMC/SD/SDIO Environment
One MMC/SD/SDIO host controller can support one MMC memory card, one SD memory card, or one
SDIO card.
Other combinations (for example, two SD cards, one MMC card, and one SD card) are not supported
through a single controller.
•
The first controller (MMC/SD/SDIO1) integrates an internal transceiver that allows a direct connection
to the MMC/SD/SDIO card (1.8 and 3V), without external transceiver. It supports 1-bit and 4-bit data
transfer modes.
•
The second controller (MMC/SD/SDIO2) allows connecting MMC/SD/SDIO cards (only 1.8V cards) or
an external device that uses the MMC/SD/SDIO interface (WLAN device for example). The second
instance also supports an external transceiver and provides direction signals for data and command. It
supports 1-bit, 4-bit and 8-bit data transfer modes. Using an external transceiver device precludes 8-bit
transfer mode.
•
The third controller (MMC/SD/SDIO3) allows connecting MMC/SD/SDIO cards (only 1.8V cards) or an
external device that uses the MMC/SD/SDIO interface (Wireless USB card for example). This interface
is used without external transceiver. It supports 1-bit, 4-bit and 8-bit data transfer modes.
24.2.1 MMC/SD/SDIO Connected to MMC, SD, or SDIO Card
shows MMC/SD/SDIOi host controller, instance 1, 2 or 3, connected to an MMC, an SD, or an
SDIO card and its related external connections.
Figure 24-3. MMC/SD/SDIO Connected to MMC, SD, or SDIO Card Without External Transceiver
24.2.2 MMC/SD/SDIO Connected to MMC, SD, or SDIO Card Through an External
Transceiver Device
This connection is supported only by the MMC/SD/SDIO2 host controller.
shows the
MMC/SD/SDIO2 host controller connected to an MMC, an SD, or an SDIO card through an external
transceiver device.
3367
SWPU177N – December 2009 – Revised November 2010
MMC/SD/SDIO Card Interface
Copyright © 2009–2010, Texas Instruments Incorporated