MMC/SD Module Configuration
Setup and Use of the Multimedia Card/Secure Digital Host Controller Application Note, Rev. 0
Freescale Semiconductor
3
Table 1. MMC/SD Card Pin Assignment
Each card has a set of information registers that hold the operating parameters and other card conditions.
See the description in
Table 2
. Details of each register can be found in card registers chapter in both the
MultiMediaCard System Specification and the SD Memory Card Specification.
Table 2. MMC/SD Card Registers
MMC or SD Identifier
Register Name
Description
Size
(Bits)
Both
CID
Card Identification Number Each card has a unique CID.
128
1
1
There can be fewer bits for the SD I/O Card, depending on implementation.
Both
RCA
Relative Card Address
Assigned by the MMC/SD module during initialization.
16
Both
DSR
Driver Stage
Configures the card’s output drivers. Use is optional, not
required.
16
Both
CSD
Card Specific Data
Contains information on the card’s operating conditions.
128
1
Both
OCR
Operation Conditions
Indicates the card’s operating voltage range. Detects restricted
cards and indicates whether power-up is complete. Use is
optional, not required.
32
Both
CSR
Card Status Register
Contains card’s error and status information. Sent to the
MMC/SD module in response format R1.
32
SD only
SCS
SD Card Status
Contains status information proprietary to the SD card (such as
protection, card type, and bus width).
512
SD only
SCR
SD Configuration Register
Contains additional configuration information only applicable to
the SD card.
64