Read Long (22H/23H); Figure 99. Read Long Command (22H/23H) - Hitachi IC25N040ATCS04-0 - Travelstar 40GN 40GB UDMA/100 4200RPM 2MB 2.5" IDE Hard Drive Specifications

13.14 Read Long (22h/23h)

Command Block Output Registers
Register
Data
Feature
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Command
Error Register
7 6 5
CRC UNC 0
0 0 0

Figure 99. Read Long command (22h/23h)

The Read Long command reads the designated one sector of data and the ECC bytes from the disk
media. It then transfers the data and ECC bytes from the device to the host.
After 512 bytes of data have been transferred, the device will keep setting DRQ = 1 to indicate that the
device is ready to transfer the ECC bytes to the host. The data is transferred 16 bits at a time and the
ECC bytes are transferred 8 bits at a time. The number of ECC bytes are 4 or 40 according to the setting
of Set Feature option. The default setting is 4 bytes of ECC data.
The command makes a single attempt to read the data and does not check the data using ECC. Whatever
is read is returned to the host.
Output parameters to the device
Sector Count
Sector Number
Cylinder High/Low
H
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
0 0 0 0 0 0 0 1
V V V V V V V V
V V V V V V V V
V V V V V V V V
1 L 1 D H H H H
0 0 1 0 0 0 1 R
4 3 2 1
IDN 0 ABT T0N AMN
V 0 V 0
This indicates the number of continuous sectors to be transferred. The Sector
Count must be set to one.
This indicates the sector number of the sector to be transferred. (L = 0) In LBA
mode, this register contains LBA bits 0–7. (L = 1)
This indicates the cylinder number of the sector to be transferred. (L = 0) In LBA
mode, this register contains LBA bits 8–15 (Low), 16–23 (High). (L = 1)
This indicates the head number of the sector to be transferred. (L = 0) In LBA
mode, this register contains LBA bits 24–27. (L = 1)
Hitachi Travelstar 60GH & 40GN hard disk drive specifications
Command Block Input Registers
Register
Data
Error
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Status
Status Register
0 7 6 5
BSY RDY DF
V 0 V 0
137
7 6 5 4 3 2 1 0
- - - - - - - -
see below
- - - - - - - V
V V V V V V V V
V V V V V V V V
V V V V V V V V
- - - - H H H H
see below
4 3 2 1 0
DSC DRQ COR IDX ERR
V 0 0 - V