Registers; Register Naming Convention; Command Register - Hitachi HTS541010G9AT00 - Travelstar 100 GB Hard Drive Specifications

9.0 Registers

In Serial ATA, the host adapter contains a set of registers that shadow the contents of the traditional device regis-
ters, referred to as the Shadow Register Block. Shadow Register Block registers are interface registers used for
delivering commands to the device or posting status from the device. About details, please refer to the Serial ATA
Spec.
In the following cases, the host adapter sets the BSY bit in its shadow Status Register and then transmits a frame to
the device containing the new regster contents.
- Command register is written in the Shadow Register Block
- Device Control register is written in the Shadow Register Block with a change of state of the SRST bit
- COMRESET is requested

9.1 Register naming convention

This specification uses the same naming conventions for the Command Block Registers as the ATA/ATAPI-6 stan-
dard. However, the register naming convention is different from that uses in the Serial ATA 1.0a specification. Fig-
ure 1 defines the corresponding of the register names used in this specification with those used in the Serial ATA
1.0a specification.
Serial ATA register
name
Features
Features (exp)
Sector count
Sector count (exp)
Sector number
Sector number (exp)
Cylinder low
Cyliner low (exp)
Cylinder high
Cylinder high (exp)
Device/head
Command
Control
Status
Error

9.2 Command Register

Register name in this
specification when
writing registers
Feature current
Feature previous
Sector count current
Sector count previous
LBA low current
LBA low previous
LBA mid current
LBA mid previous
LBA high current
LBA high previous
Device
Command
Device Control
N/A
N/A
Travelstar 5K100 (Serial ATA) Hard Disk Drive Specification
Register name in this
specification when
reading registers
Sector count HOB=0
Sector count HOB=1
LBA low HOB=0
LBA low HOB=1
LBA mid HOB=0
LBA mid HOB=1
LBA mid HOB=0
LBA mid HOB=1
Device
N/A
N/A
Status
Error
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