Samsung WA31273A Technical Manual page 54

AT INTERFACE and ATA COMMANDS
The physical sector address is made up of three fields: the sector number, the head
number and the cylinder number. Sectors are numbered from 0 to a device specific
maximum value which cannot exceed 255. Heads are numbered from 0 to a device
specific maximum value which cannot exceed 15. Cylinders are numbered from 0 to a
device specific maximum value which cannot exceed 65,535. Typically, sequential access
to the media is accomplished by treating the sector number as the least significant
portion, the head number as the mid-portion, and the cylinder number as the most
significant portion of the CHS address.
In LBA (Logical Block Address) mode the sectors on the device are assumed to be
linearly mapped with an Initial definition of : LBA 0 = (Cylinder 0, head 0, sector 0).
Irrespective of translate mode geometry set by the host, the LBA address of a given
sector does not change:
LBA = ((cylinder * heads_per_cylinder + heads) * sectors_per_track) + sector - 1
6-3-2 I/O Register-Address
Communication to or from the drive is through an I/O Register that routes the input or
output data to or from registers addressed by a code on signals from the host (CS1FX-,
CS3FX-, DA2, DA1, DA0, DIOR- and DIOW-).
The Command Block Registers are used for sending commands to the drive or posting
status from the drive.
The Control Block Registers are used for drive control and to post alternate status. Table
6-3 lists these registers and the addresses that select them.
CS1FX- CS3FX-
N
N
N
N
N
A
A
6-
10 WA31273A / WA32543A / WA33203A / WA3216A / WA31083A / WA32162A
Table 6-3. I/O Port Function/Selection Address
Address
DA2 DA1
N X X
A 0 X
A 1 0
A 1 1
A 1 1
N 0 0
N 0 0
DA0 READ(DIOR-)
Control Block Registers
X High Impedance
X High Impedance
X High Impedance
0 Alternate Status
1 Device Address
Command Block Registers
0 Data
1 Error Register
Functions
WRITE(DIOW-)
Not Used
Not Used
Not Used
Device Control
Not Used
Data
Features