Hitachi HTS421210H9AT00, Specifications

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Travelstar 4K120 Hard Disk Drive Specification
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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.
CS0- CS1- DA02 DA01 DA00 DIOR- = 0 (Read) DIOW- = 0 (Write)
Command Block Registers
0 1 0 0 0 Data Reg. Data Reg.
0 1 0 0 1 Error Reg. Features Reg.
0 1 0 1 0 Sector count Reg. Sector count Reg.
0 1 0 1 1 LBA low Reg LBA low Reg.
0 1 1 0 0 LBA mid Reg. LBA mid Reg.
0 1 1 0 1 LBA high Reg. LBA high Reg.
0 1 1 1 0 Drive Reg. Device Reg.
0 1 1 1 1 Status Reg. Command Reg.
Control Block Registers
1 0 1 1 0 Alt. Status Reg. Device control Reg.
1 0 1 1 1 Drive address Reg. –