Toshiba 4006GAH Manual Do Utilizador

360050398

Toshiba Corporation Digital Media Network Company

Page 62 of 157

10.8.5 Read Sector (20h/21h)

COMMAND CODE

0 0 1 0 0 0 0 X

NORMAL COMPLETION

drive no.

no change

starting cylinder

last possible

starting head

last possible

starting sector

last possible

no. of sector to read

00H

change

LBA

staring address

last address

Setting BSY bit, the drive will seek to the target cylinder if the head is not on target track ( implied seek ), select
the head and begin to read the number of sector defined in SC register ( 1-256 ) starting from the target sector.
After finding ID of target sector and having 1 sector of data read into the buffer RAM, the drive sets DRQ in
status register and generates interrupt to report to the host that the drive is ready to transfer the next data.
  In case of multi-sector transfer, DRQ bit is reset and BSY is set after 1 sector transfer to prepare for the next
sector transfer.
  An uncorrectable data can also be transferred but the subsequent operation will terminate at the cylinder, head,
and sector (or LBA) position in the TASK FILE register. When a sector is ready to be read by the host, an
interrupt    is issued. After the last sector is read by the host, no interrupt is issued at the end of a command.

10.8.6 Read Sector EXT (24h)

COMMAND CODE

0 0 1 0 0 1 0 0

NORMAL COMPLETION

drive no.

no change

LBA

Low

Current

LBA(7:0)

LBA(31:24)

HOB=0
HOB=1

last address
last address

LBA

Mid

Current

LBA(15:8)

LBA(39:32)

HOB=0
HOB=1

last address
last address

LBA
High

Current

LBA(23:16)
LBA(47:40)

HOB=0
HOB=1

last address
last address

SC Current

sector count(7:0)

sector count(15:8)

HOB=0
HOB=1

00H
00H

FT Current

reserved
reserved

HOB=0
HOB=1

no change
no change

Setting BSY bit, the drive will seek to the target cylinder if the head is not on target track ( implied seek ), select
the head and begin to read the number of sector defined in SC register ( 1-65536 ) starting from the target
sector. After finding ID of target sector and having 1 sector of data read into the buffer RAM, the drive sets DRQ
in status register and generates interrupt to report to the host that the drive is ready to transfer the next data.
  In case of multi-sector transfer, DRQ bit is reset and BSY is set after 1 sector transfer to prepare for the next
sector transfer.
  An uncorrectable data can also be transferred but the subsequent operation will terminate at the LBA position
in the TASK FILE register. When a sector is ready to be read by the host, an interrupt is issued. After the last
sector is read by the host, no interrupt is issued at the end of a command.
  This command is available in LBA addressing only.