7.11 Addressing of HDD registers
The host addresses the drive through a set of registers called a Task File. These registers are mapped into the host's
I/O space. Two chip select lines (CS0- and CS1-) and three address lines (DA00–02) are used to select one of these
registers, while a DIOR- or DIOW- is provided at the specified time.
The chip select line CS0- is used to address the Command Block registers while the CS1- is used to address Con-
trol Block registers.
The following table shows the I/ O address map.
Table 37: I/O address map
CS0-
CS1-
DA02-
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
0
1
0
DA01
DA00
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
1
1
0
1
1
1
Travelstar 7K100 Hard Disk Drive Specification
DIOR- = 0 (Read)
Command Block Registers
Data Reg.
Error Reg.
Sector count Reg.
LBA low Reg.
LBA mid Reg.
LBA high Reg.
Device Reg.
Status Reg.
Control Block Registers
Alt. Status Reg.
Drive address Reg.
52
DIOW- = 0 (Write)
Data Reg.
Features Reg.
Sector count Reg.
LBA low Reg.
LBA mid Reg.
LBA high Reg.
Device Reg.
Command Reg.
Device control Reg.
–