Write Dma (Cah); Write Long (32H) - Samsung WA31273A Technical Manual

AT INTERFACE and ATA COMMANDS

6-4-24 Write DMA (CAh)

This command executes in a similar manner to Write Sector(s) except for the following
• the host initializes a slave-DMA channel prior to issuing the command
• data transfers are qualified by DMARQ and are performed by the slave-DMA
channel
• the drive issues only one interrupt per command to indicate that data transfer has
terminated and status is available.
Any error encountered during Write DMA execution results in the termination of data
transfer. The drive issues an interrupt to indicate that data transfer has terminated and
status is available in the Error Register. The error posting is the same as that of the Write
Sector(s) command.

6-4-25 Write Long (32h)

This command is similar to the Write Sectors command except that it writes the data and
the ECC bytes directly from the sector buffer; the drive does not generate the ECC bytes
itself. Only single sector Write Long operations are supported.
The transfer of the ECC bytes shall be 8 bits wide, and 4 or 11 bytes long.
6-4-26 Write Sector(s) (30h)
This command writes from 1 to 256 sectors as specified in the Sector Count Register (a
sector count of zero requests 256 sectors), beginning at the specified sector. Refer to
Section 6.7 for the DRQ, IRQ and BSY protocol on data transfers.
If the drive is not already on the desired track, an implied seek is performed. Once at the
desired track, the drive searches for the appropriate ID field.
If retries are disabled and two index pulses have occurred without error free reading of
the requested ID, an ID Not Found error is posted.
If retries are enabled, up to a predefined number of attempts may be made to read the
requested ID before posting an error.
If the ID is read correctly, the data loaded in the buffer is written to the data field of the
sector, followed by the ECC bytes. Upon command completion, the Command Block
Registers contain the cylinder, head, and sector number of the last sector written in CHS
mode, logical block address in LBA mode.
If an error occurs during a write of more than one sector, writing terminates at the sector
where the error occurs. The Command Block Registers contain the cylinder, head, and
sector number of the sector where the error occurred in CHS mode, logical block
address in LBA mode. The host may then read the command block to determine what
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36 WA31273A / WA32543A / WA33203A / WA3216A / WA31083A / WA32162A