Status
and
registers
FIFO
CLK
divider
MMC/SD
interface
MMC/SD
card
interface
CPU
DMA requests
Interrupts
Introduction
1267
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multimedia Card (MMC)/Secure Digital (SD) Card Controller
26.1 Introduction
26.1.1 Purpose of the Peripheral
A number of applications use the multimedia card (MMC)/secure digital (SD) card to provide removable
data storage. The MMC/SD card controller provides an interface to external MMC and SD cards. The
communication between the MMC/SD card controller and MMC/SD card(s) is performed according to the
MMC/SD protocol.
26.1.2 Features
The MMC/SD card controller has the following features:
•
Supports interface to multimedia cards (MMC)
•
Supports interface to secure digital (SD) memory cards
•
Ability to use the MMC/SD protocol and Secure Digital Input Output (SDIO) protocol
•
Programmable frequency of the clock that controls the timing of transfers between the MMC/SD
controller and memory card
•
512-bit read/write FIFO to lower system overhead
•
Signaling to support enhanced direct memory access (EDMA) transfers (slave)
•
Maximum clock to MMC varies based on core voltage (see your device-specific data manual)
•
Maximum clock to SD varies based on core voltage (see your device-specific data manual)
26.1.3 Functional Block Diagram
The MMC/SD card controller transfers data between the CPU and the EDMA controller on one side and
the MMC/SD card on the other side, as shown in
. This means you have a choice of
performing data transfers using the CPU or EDMA as a mechanism to move data between the device
memory and the FIFO. The CPU and the EDMA controller can read from or write to the data in the card by
accessing the registers in the MMC/SD controller.
Figure 26-1. MMC/SD Card Controller Block Diagram
26.1.4 Supported Use Case Statement
The MMC/SD card controller supports the following user cases:
•
MMC/SD card identification
•
MMC/SD single-block read using CPU
•
MMC/SD single-block read using EDMA
•
MMC/SD single-block write using CPU
•
MMC/SD single-block write using EDMA
•
MMC/SD multiple-block read using CPU
•
MMC/SD multiple-block read using EDMA