7.2.5 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.
–
Drive address Reg.
1
1
1
0
1
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 42. I/O address map
During DMA operation (from writing to the command register until an interrupt) all registers are not acces-
sible.
For example, the host is not supposed to read status register contents before interrupt (the value is in-
valid).
7.2.6 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 (>8.3MB/sec) a modification in the system design is recommended to
reduce cable noise and/or cross-talk, such as a shorter cable, bus termination, or a shielded cable.
For systems operating with Ultra DMA mode 3 or 4, 80-conductor ATA cable assembly (SFF-8049) shall
be used.
Deskstar 40GV & 75GXP hard disk drive specifications
40
Содержание DTLA-305040 - Deskstar 41.1 GB Hard Drive
Страница 8: ...This page intentionally left blank...
Страница 16: ...This page intentionally left blank...
Страница 17: ...Part 1 Functional specification Deskstar 40GV 75GXP hard disk drive specifications 5...
Страница 18: ...This page intentionally left blank...
Страница 20: ...This page intentionally left blank...
Страница 30: ...This page intentionally left blank...
Страница 32: ...This page intentionally left blank...
Страница 34: ...This page intentionally left blank...
Страница 76: ...This page intentionally left blank...
Страница 77: ...Part 2 Interface specification Deskstar 40GV 75GXP hard disk drive specifications 65...
Страница 78: ...This page intentionally left blank...
Страница 80: ...This page intentionally left blank...
Страница 108: ...This page intentionally left blank...
Страница 116: ...This page intentionally left blank...
Страница 206: ...This page intentionally left blank...
Страница 210: ...This page intentionally left blank...