Hitachi HDT725025VLA380 Specifications - Page 199

Read Sectors 20h/21h

Page 199 highlights

12.23 Read Sectors (20h/21h) Table 112: Read Sectors Command (20h/21h) Command Block Output Registers Register 7 6 5 4 3 2 1 0 Data Feature Sector Count V V V V V V V V Sector Number V V V V V V V V Cylinder Low V V V V V V V V Cylinder High V V V V V V V V Device/Head 1 L 1 D H H H H Command 0 0 1 0 0 0 0 R 76 CRC UNC 0V Error Register 54 3 2 1 0 0 IDN 0 ABT T0N AMN 0V 0 V 0 0 Command Block Input Registers Register 7 6 5 4 3 2 1 0 Data Error see below Sector Count V V V V V V V V Sector Number V V V V V V V V Cylinder Low V V V V V V V V Cylinder High V V V V V V V V Device/Head - - - - H H H H Status see below Status Register 7 654 3 2 1 0 BSY RDY DF DSC DRQ COR IDX ERR 0 V0V - 0 - V The Read Sectors command reads one or more sectors of data from disk media and then transfers the data from the device to the host. The sectors are transferred through the Data Register 16 bits at a time. If an uncorrectable error occurs the read will be terminated at the failing sector. Output parameters to the device Sector Count This indicates the number of continuous sectors to be transferred. If zero is specified, 256 sectors will be transferred. Sector Number This is the sector number of the first sector to be transferred. (L =0) In LBA mode this register contains the LBA bits 0-7. (L = 1) Cylinder High/Low This is the cylinder number of the first sector to be transferred. (L = 0) In LBA mode this register contains the LBA bits 8-15 (Low) and bits 16-23 (High). (L = 1) H This is the head number of the first sector to be transferred. (L = 0) In LBA mode this register contains the LBA bits 24-27. (L = 1) R This is the retry bit, but this bit is ignored. Input parameters from the device Sector Count This is the number of requested sectors not transferred. This will be zero, unless an unrecoverable error occurs. Sector Number This is the sector number of the last transferred sector. (L = 0) In LBA mode this register contains the current LBA bits 0-7. (L = 1) Deskstar T7K500 Hard Disk Drive Specification 185

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Deskstar T7K500 Hard Disk Drive Specification
185
12.23
Read Sectors (20h/21h)
Table 112: Read Sectors Command (20h/21h)
The Read Sectors command reads one or more sectors of data from disk media and then transfers the data from the
device to the host.
The sectors are transferred through the Data Register 16 bits at a time.
If an uncorrectable error occurs the read will be terminated at the failing sector.
Output parameters to the device
Sector Count
This indicates the number of continuous sectors to be transferred. If zero is specified,
256 sectors will be transferred.
Sector Number
This is the sector number of the first sector to be transferred. (L =0)
In LBA mode this register contains the LBA bits 0–7. (L = 1)
Cylinder High/Low
This is the cylinder number of the first sector to be transferred. (L = 0)
In LBA mode this register contains the LBA bits 8–15 (Low) and bits 16–23 (High).
(L = 1)
H
This is the head number of the first sector to be transferred. (L = 0)
In LBA mode this register contains the LBA bits 24–27. (L = 1)
R
This is the retry bit, but this bit is ignored.
Input parameters from the device
Sector Count
This is the number of requested sectors not transferred. This will be zero, unless an unre-
coverable error occurs.
Sector Number
This is the sector number of the last transferred sector. (L = 0)
In LBA mode this register contains the current LBA bits 0–7. (L = 1)
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
- - - - - - - -
Data
- - - - - - - -
Feature
- - - - - - - -
Error
see below
Sector Count
V V V V V V V V
Sector Count
V V V V V V V V
Sector Number
V V V V V V V V
Sector Number
V V V V V V V V
Cylinder Low
V V V V V V V V
Cylinder Low
V V V V V V V V
Cylinder High
V V V V V V V V
Cylinder High
V V V V V V V V
Device/Head
1 L 1 D H H H H
Device/Head
- - - - H H H H
Command
0 0 1 0 0 0 0 R
Status
see below
Error Register
Status Register
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CRC UNC 0 IDN 0 ABT T0N AMN
BSY RDY DF DSC DRQ COR IDX ERR
0
V
0
V
0
V
0
0
0
V
0
V
-
0
-
V