Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet
Product codes
AT91SAM9N12-EK
585
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
35.9.2 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.
35.10 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.
FAST_IO (CMD39): Used for single register access to the ATA taskfile registers, 8 bit access only.
RW_MULTIPLE_REGISTERS (CMD60): used to issue an ATA command or to access the control/status registers.
RW_MULTIPLE_BLOCK (CMD61): used to transfer data for an ATA command.
CE-ATA utilizes the same MMC command sequences for initialization as traditional MMC devices.
35.10.1 Executing an ATA Polling Command
1.
Issue READ_DMA_EXT with RW_MULTIPLE_REGISTER (CMD60) for 8kB of DATA.
2.
Read the ATA status register until DRQ is set.
3.
Issue RW_MULTIPLE_BLOCK (CMD61) to transfer DATA.
4.
Read the ATA status register until DRQ && BSY are set to 0.
35.10.2 Executing an ATA Interrupt Command
1.
Issue READ_DMA_EXT with RW_MULTIPLE_REGISTER (CMD60) for 8kB of DATA with nIEN field set to zero to
enable the command completion signal in the device.
enable the command completion signal in the device.
2.
Issue RW_MULTIPLE_BLOCK (CMD61) to transfer DATA.
3.
Wait for Completion Signal Received Interrupt.
35.10.3 Aborting an ATA Command
If the host needs to abort an ATA command prior to the completion signal it must send a special command to avoid
potential collision on the command line. The SPCMD field of the HSMCI_CMDR must be set to 3 to issue the CE-ATA
completion Signal Disable Command.
potential collision on the command line. The SPCMD field of the HSMCI_CMDR must be set to 3 to issue the CE-ATA
completion Signal Disable Command.
35.10.4 CE-ATA Error Recovery
Several methods of ATA command failure may occur, including:
No response to an MMC command, such as RW_MULTIPLE_REGISTER (CMD60).
CRC is invalid for an MMC command or response.
CRC16 is invalid for an MMC data packet.
ATA Status register reflects an error by setting the ERR bit to one.
The command completion signal does not arrive within a host specified time out period.
Error conditions are expected to happen infrequently. Thus, a robust error recovery mechanism may be used for each
error event. The recommended error recovery procedure after a timeout is:
error event. The recommended error recovery procedure after a timeout is:
Issue the command completion signal disable if nIEN was cleared to zero and the RW_MULTIPLE_BLOCK
(CMD61) response has been received.
(CMD61) response has been received.
Issue STOP_TRANSMISSION (CMD12) and successfully receive the R1 response.
Issue a software reset to the CE-ATA device using FAST_IO (CMD39).