Features Register (Formerly Write Precomp Register); Sector Count; Sector Number - Seagate Medalist ST3636A Product Manual

Chapter 6

Features Register (formerly Write Precomp Register)

Sector Count

Sector Number

Page 36
Port Address:
Chip Select:
Register Address:
Function:
Description: This register was previously used to set write precompensation in
non-intelligent (pre-IDE) disk drives. This drive uses this register for
commands EF and B0. The ATA specification defines this register as the
Features register.
Port Address:
Chip Select:
Register Address:
Function:
Description: This register defines the number of sectors of data to be
transferred on read or write commands.
If the value in this register is zero, a count of 256 sectors is specified. This count
is decremented as each sector is read, such that the register contains the
number of sectors left to access in the event of an error in a multi-sector
operation.
The contents of this register define the number of sectors per track when
executing an Initialize Device Parameters command. This register is also
used in the power commands to provide the power-down time-out parameter
and status.
Port Address:
Chip Select:
Register Address:
Function:
CHS Description: This register contains the starting sector number for any
disk access.
LBA Description: This register contains bits 0-7 of the logical block address.
At the completion of each sector and at the end of the command, this register is
updated to reflect the last sector read correctly or the sector on which an error
occurred. During multiple sector transfers, this register is updated to point at
the next sector to be read/written if the previous sector's operation was
successful.
1F1
-HOST CS0
1
Write only
1F2
-HOST CS0
2
Read/Write
1F3
-HOST CS0
3
Read/Write
Register Addresses and Functions
ST3636A/ST31082A/ST31276A