Atmel Evaluation Kit for the SAM4E Series of Flash Microcontrollers ATSAM4E-EK ATSAM4E-EK Data Sheet
Product codes
ATSAM4E-EK
SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
1116
41.9
SD/SDIO Card Operation
The High Speed MultiMedia Card Interface allows processing of SD Memory (Secure Digital Memory Card) and
SDIO (SD Input Output) Card commands.
SDIO (SD Input Output) Card commands.
SD/SDIO cards are based on the MultiMedia Card (MMC) format, but are physically slightly thicker and feature
higher data transfer rates, a lock switch on the side to prevent accidental overwriting and security features. The
physical form factor, pin assignment and data transfer protocol are forward-compatible with the High Speed
MultiMedia Card with some additions. SD slots can actually be used for more than flash memory cards. Devices
that support SDIO can use small devices designed for the SD form factor, such as GPS receivers, Wi-Fi or
Bluetooth adapters, modems, barcode readers, IrDA adapters, FM radio tuners, RFID readers, digital cameras
and more.
higher data transfer rates, a lock switch on the side to prevent accidental overwriting and security features. The
physical form factor, pin assignment and data transfer protocol are forward-compatible with the High Speed
MultiMedia Card with some additions. SD slots can actually be used for more than flash memory cards. Devices
that support SDIO can use small devices designed for the SD form factor, such as GPS receivers, Wi-Fi or
Bluetooth adapters, modems, barcode readers, IrDA adapters, FM radio tuners, RFID readers, digital cameras
and more.
SD/SDIO is covered by numerous patents and trademarks, and licensing is only available through the Secure
Digital Card Association.
Digital Card Association.
The SD/SDIO Card communication is based on a 9-pin interface (Clock, Command, 4 x Data and 3 x Power lines).
The communication protocol is defined as a part of this specification. The main difference between the SD/SDIO
Card and the High Speed MultiMedia Card is the initialization process.
The communication protocol is defined as a part of this specification. The main difference between the SD/SDIO
Card and the High Speed MultiMedia Card is the initialization process.
The SD/SDIO Card Register (HSMCI_SDCR) allows selection of the Card Slot and the data bus width.
The SD/SDIO Card bus allows dynamic configuration of the number of data lines. After power up, by default, the
SD/SDIO Card uses only DAT0 for data transfer. After initialization, the host can change the bus width (number of
active data lines).
SD/SDIO Card uses only DAT0 for data transfer. After initialization, the host can change the bus width (number of
active data lines).
41.9.1 SDIO Data Transfer Type
SDIO cards may transfer data in either a multi-byte (1 to 512 bytes) or an optional block format (1 to 511 blocks),
while the SD memory cards are fixed in the block transfer mode. The TRTYP field in the HSMCI Command
Register (HSMCI_CMDR) allows to choose between SDIO Byte or SDIO Block transfer.
while the SD memory cards are fixed in the block transfer mode. The TRTYP field in the HSMCI Command
Register (HSMCI_CMDR) allows to choose between SDIO Byte or SDIO Block transfer.
The number of bytes/blocks to transfer is set through the BCNT field in the HSMCI Block Register (HSMCI_BLKR).
In SDIO Block mode, the field BLKLEN must be set to the data block size while this field is not used in SDIO Byte
mode.
In SDIO Block mode, the field BLKLEN must be set to the data block size while this field is not used in SDIO Byte
mode.
An SDIO Card can have multiple I/O or combined I/O and memory (called Combo Card). Within a multi-function
SDIO or a Combo card, there are multiple devices (I/O and memory) that share access to the SD bus. In order to
allow the sharing of access to the host among multiple devices, SDIO and combo cards can implement the
optional concept of suspend/resume (Refer to the SDIO Specification for more details). To send a suspend or a
resume command, the host must set the SDIO Special Command field (IOSPCMD) in the HSMCI Command
Register.
SDIO or a Combo card, there are multiple devices (I/O and memory) that share access to the SD bus. In order to
allow the sharing of access to the host among multiple devices, SDIO and combo cards can implement the
optional concept of suspend/resume (Refer to the SDIO Specification for more details). To send a suspend or a
resume command, the host must set the SDIO Special Command field (IOSPCMD) in the HSMCI Command
Register.
41.9.2 SDIO Interrupts
Each function within an SDIO or Combo card may implement interrupts (Refer to the SDIO Specification for more
details). In order to allow the SDIO card to interrupt the host, an interrupt function is added to a pin on the DAT[1]
line to signal the card’s interrupt to the host. An SDIO interrupt on each slot can be enabled through the HSMCI
Interrupt Enable Register. The SDIO interrupt is sampled regardless of the currently selected slot.
details). In order to allow the SDIO card to interrupt the host, an interrupt function is added to a pin on the DAT[1]
line to signal the card’s interrupt to the host. An SDIO interrupt on each slot can be enabled through the HSMCI
Interrupt Enable Register. The SDIO interrupt is sampled regardless of the currently selected slot.
41.10 CE-ATA Operation
CE-ATA maps the streamlined ATA command set onto the MMC interface. The ATA task file is mapped onto MMC
register space.
register space.
CE-ATA utilizes five MMC commands:
GO_IDLE_STATE (CMD0): used for hard reset.
STOP_TRANSMISSION (CMD12): causes the ATA command currently executing to be aborted.