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Native packets
Native
signals
CMD
DAT0, DAT0-3,
or DAT0-7
CLK
EDMA
CPU
Memory
MMCs or SD cards
MMC/SD
controller
Introduction
1268
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multimedia Card (MMC)/Secure Digital (SD) Card Controller
•
MMC/SD multiple-block write using CPU
•
MMC/SD multiple-block write using EDMA
26.1.5 Industry Standard(s) Compliance Statement
The MMC/SD card controller supports the following industry standards (with the exception noted below):
•
MMC (Multimedia Card) Specification v4.0
•
SD (Secure Digital) Physical Layer Specification v1.1
•
SDIO (Secure Digital Input Output) Specification v2.0
The information in this chapter assumes that you are familiar with these standards.
The MMC/SD controller does not support the SPI mode of operation.
26.2 Architecture
The MMC/SD controller uses the MMC/SD protocol to communicate with the MMC/SD cards. You can
configure the MMC/SD controller to work as an MMC or SD controller, based on the type of card the
controller is communicating with.
summarizes the MMC/SD mode interface.
illustrates how the controller interfaces to the cards in MMC/SD mode.
In the MMC/SD mode, the MMC controller supports one or more MMC/SD cards. Regardless of the
number of cards connected, the MMC/SD controller selects one by using identification broadcast on the
data line. The following MMC/SD controller pins are used:
•
MMCSD_CMD: This pin is used for two-way communication between the connected card and the
MMC/SD controller. The MMC/SD controller transmits commands to the card and the memory card
drives responses to the commands on this pin.
•
MMCSD_DAT0, MMCSD_DAT0-3, or MMCSD_DAT0-7: MMC cards only use one data line (DAT0),
four data lines (DAT0-3), or eight data lines (DAT0-7), and SD cards use one data line (DAT0) or four
data lines (DAT0-3). The number of MMCSD_DAT pins (the data bus width) is set by the WIDTH bit in
the MMC control register (MMCCTL), see
•
MMCSD_CLK: This pin provides the clock to the memory card from the MMC/SD controller.
Figure 26-2. MMC/SD Controller Interface Diagram