Travelstar 5K100 Hard Disk Drive Specification
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13.14 Read DMA EXT (25h)
Table 84: Read DMA EXT (25h)
The Read DMA command reads one or more sectors of data from disk media, then transfers the data from the
device to the host.
The sectors are transferred through the Data Register 16 bits at a time.
The host initializes a slave-DMA channel prior to issuing the command. The data transfers are qualified by
DMARQ and are performed by the slave-DMA channel. The device issues only one interrupt per command to indi-
cate that data transfer has terminated and status is available.
If an uncorrectable error occurs, the read will be terminated at the failing sector
Output parameters to the device
Sector Count Current This indicates the number of sectors to be transferred low order, bits (7-0)
Sector Count Previous This indicates the number of sectors to be transferred high order, bits (15-8). If 0000h in
the Sector Count register is specified, 65.536 sectors will be transferred.
LBA Low Current LBA (7-0)
LBA Low Previous LBA (31-24)
LBA Mid Current LBA (15-8)
LBA Mid Previous LBA (39-32)
LBA High Current LBA (23-16)
LBA High Previous LBA (47-40)
Command Block Output Registers Command Block Input Registers
Register 7 6 5 4 3 2 1 0 Register 7 6 5 4 3 2 1 0
Data Low - - - - - - - - Data Low - - - - - - - -
Data High - - - - - - - - Data High - - - - - - - -
Feature
Current - - - - - - - - Error see below
Previous - - - - - - - -
Sector
Count
Current V V V V V V V V
Sector
Count
HOB=0 - - - - - - - -
Previous V V V V V V V V HOB=1 - - - - - - - -
LBA Low
Current V V V V V V V V
LBA Low
HOB=0 V V V V V V V V
Previous V V V V V V V V HOB=1 V V V V V V V V
LBA Mid
Current V V V V V V V V
LBA Mid
HOB=0 V V V V V V V V
Previous V V V V V V V V HOB=1 V V V V V V V V
LBA High
Current V V V V V V V V
LBA High
HOB=0 V V V V V V V V
Previous V V V V V V V V HOB=1 V V V V V V V V
Device 1 1 1 D - - - - Device V - - - - - - -
Command 0 0 1 0 0 1 0 1 Status See below ...
Error Register Status Register
7654321 0 76543 21 0
CRC UNC 0 IDN 0 ABT T0N AMN BSY RDY DF DSC DRQ COR IDX ERR
VV0V0V0 0 0V0V- 0- V