Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Ficha De Dados

1117

SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14



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.

1.

Issue READ_DMA_EXT with RW_MULTIPLE_REGISTER (CMD60) for 8 KB 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 configured to 0.

1.

Issue READ_DMA_EXT with RW_MULTIPLE_REGISTER (CMD60) for 8 KB of DATA with nIEN field set to zero 
to enable the command completion signal in the device.

2.

Issue RW_MULTIPLE_BLOCK (CMD61) to transfer DATA.

3.

Wait for Completion Signal Received Interrupt.

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.

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:



Issue the command completion signal disable if nIEN was cleared to zero and the RW_MULTIPLE_BLOCK 
(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).

If STOP_TRANMISSION (CMD12) is successful, then the device is again ready for ATA commands. However, if
the error recovery procedure does not work as expected or there is another timeout, the next step is to issue
GO_IDLE_STATE (CMD0) to the device. GO_IDLE_STATE (CMD0) is a hard reset to the device and completely
resets all device states.

Note that after issuing GO_IDLE_STATE (CMD0), all device initialization needs to be completed again. If the CE-
ATA device completes all MMC commands correctly but fails the ATA command with the ERR bit set in the ATA
Status register, no error recovery action is required. The ATA command itself failed implying that the device could
not complete the action requested, however, there was no communication or protocol failure. After the device
signals an error by setting the ERR bit to one in the ATA Status register, the host may attempt to retry the
command.