Datasheet
547
SAM9261 [DATASHEET]
Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16
34. MultiMedia Card Interface (MCI)
34.1 Overview
The MultiMedia Card Interface (MCI) supports the MultiMedia Card (MMC) Specification V2.2 and the SD Memory
Card Specification V1.0.
The MCI includes a command register, response registers, data registers, timeout counters and error detection
logic that automatically handle the transmission of commands and, when required, the reception of the associated
responses and data with a limited processor overhead.
The MCI supports stream, block and multi-block data read and write, and is compatible with the Peripheral DMA
Controller (PDC) channels, minimizing processor intervention for large buffer transfers.
The MCI operates at a rate of up to Master Clock divided by 2 and supports the interfacing of 2 slot(s). Each slot
may be used to interface with a MultiMediaCard bus (up to 30 Cards) or with a SD Memory Card. Only one slot can
be selected at a time (slots are multiplexed). A bit field in the SD Card Register performs this selection.
The SD Memory Card communication is based on a 9-pin interface (clock, command, four data and three power
lines) and the MultiMedia Card on a 7-pin interface (clock, command, one data, three power lines and one
reserved for future use).
The SD Memory Card interface also supports MultiMedia Card operations. The main differences between SD and
MultiMedia Cards are the initialization process and the bus topology.
34.2 Embedded Characteristics
Compatibility with MultiMedia Card Specification Version 2.2
Compatibility with SD Memory Card Specification Version 1.0
Cards clock rate up to Master Clock divided by 2
Embedded power management to slow down clock rate when not used
Each MCI has two slots, each supporting
One slot for one MultiMedia Card Bus (up to 30 cards) or
One SD Memory Card
Support for stream, block and multi-block data read and write
Supports connection to Peripheral DMA Controller (PDC)
. Minimizes processor intervention for large buffer transfers