IBM Deskstar 120 GXP, Технические характеристики

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6.2.5 Addressing of registers
The host addresses the drive through a set of registers called the Task File. These registers are mapped
into the I/ O space of the host. Two chip select lines (CS0– and CS1–) and three address lines (DA0-02)
are used to select one of these registers, while a DIOR– or DIOW– is provided at the specified time.
The CS0– is used to address Command Block registers. while the CS1– is used to address Control Block
registers.
The following table shows the I/ O address map.
Device control Reg. Alt. Status Reg. 0 1 1 0 1
Control Block Registers
Command Reg. Status Reg. 1 1 1 1 0
Drive/Head Reg. Drive/Head Reg. 0 1 1 1 0
Cylinder high Reg. Cylinder high Reg. 1 0 1 1 0
Cylinder low Reg. Cylinder low Reg. 0 0 1 1 0
Sector number Reg. Sector number Reg. 1 1 0 1 0
Sector count Reg. Sector count Reg. 0 1 0 1 0
Features Reg. Error Reg. 1 0 0 1 0
Data Reg. Data Reg. 0 0 0 1 0
Command Block Registers
DIOW– = 0 (Write) DIOR– = 0 (Read) DA0 DA1 DA2 CS1– CS0–
Figure 43. I/O address map
Note: "Addr" field is shown as an example.
During DMA operation (from writing to the command register until an interrupt) not all registers are acces-
sible. For example, the host is not supposed to read status register contents before interrupt (the value is
invalid).
6.2.6 Cabling
The maximum cable length from the host system to the drive plus circuit pattern length in the host system
shall not exceed 18 inches.
For higher data transfer application (>8.3 MB/s) a modification in the system design is recommended to
reduce cable noise and cross-talk, such as a shorter cable, bus termination, or a shielded cable.
For systems operating with Ultra DMA mode 3, 4, and 5, 80-conductor ATA cable assembly (SFF-8049)
shall be used.
Deskstar 120GXP hard disk drive specifications
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