SST55LD019M datasheet(35/59 Pages) SST

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Advance Information

ATA Flash Disk Controller

SST55LD019M

S71312-01-000

12/06

10.2.1.11 Read-DMA - C8H

This command executes in a similar manner to the Read-Sector(s) command except for the following:

- the host initializes the DMA channel prior to issuing the command;

- data transfers are qualified by DMARQ and are performed by the DMA channel;

- the ATA Flash Disk Controller issues only one interrupt per command to indicate that data transfer has

terminated and status is available.

During the DMA transfer phase of a Read-DMA command, the ATA Flash Disk Controller will provide

the status of the BSY bit or the DRQ bit until the command is completed.

10.2.1.12 Read-Multiple - C4H

Note: The current revision of the ATA Flash Disk Controller can support up to a block count of 1 as indicated in the Identify-Drive Com-

mand information.

The Read-Multiple command is similar to the Read-Sector(s) command. Interrupts are not generated

on every sector, but on the transfer of a block which contains the number of sectors defined by a Set

Multiple command.

Command execution is identical to the Read-Sectors operation except that the number of sectors

defined by a Set Multiple command are transferred without intervening interrupts. DRQ qualification of

the transfer is required only at the start of the data block, not on each sector.

The block count of sectors to be transferred without intervening interrupts is programmed by the Set-

Multiple-Mode command, which must be executed prior to the Read-Multiple command. When the

Read-Multiple command is issued, the Sector Count register contains the number of sectors (not the

number of blocks or the block count) requested. If the number of requested sectors is not evenly

divisible by the block count, as many full blocks as possible are transferred, followed by a final, partial

block transfer. The partial block transfer is for n sectors, where

n = remainder (sector count/block count).

If the Read-Multiple command is attempted before the Set-Multiple-Mode command has been executed

or when Read-Multiple commands are disabled, the Read-Multiple operation is rejected with an

Bit ->

76543210

Command (7)

C8H

C/D/H (6)

LBA

Drive

Head (LBA 27-24)

Cyl High (5)

Cylinder High (LBA 23-16)

Cyl Low (4)

Cylinder Low (LBA 15-8)

Sec Num (3)

Sector Number (LBA 7-0)

Sec Cnt (2)

Sector Count

Feature (1)