Addressing Of Hdd Registers; Cabling - IBM DTTA-351010 - Deskstar 10.1 GB Hard Drive Specifications

6.2.5 Addressing of HDD Registers

The host addresses the drive through a set of registers called the 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 -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.
C S 0 C S 1 D A 0 2 D A 0 1 D A 0 0
0 1 0
0 1 0
0 1 0
0 1 0
0 1 1
0 1 1
0 1 1
0 1 1
1 0 1
1 0 1
Figure 29. I/O address map
Note: "Addr." field is shown just as an example.
During D M A 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 invalid).

6.2.6 Cabling

The maximum cable length from the host system to the H D D plus circuit pattern length in the host system
shall not exceed 18 inches.
For higher data transfer application(>8.3MB/sec), a consideration in system design is recommended to
reduce cable noise and/or cross-talk, such as shorter cable, bus termination, shielded cable, etc.
D I O R = 0 ( R e a d )
C o m m a n d B l o c k R e g i s t e r s
0 0 D a t a R e g .
0 1 E r r o r R e g .
1 0 S e c t o r c o u n t R e g .
1 1 S e c t o r n u m b e r R e g .
0 0 C y l i n d e r l o w R e g .
0 1 C y l i n d e r h i g h R e g .
1 0 D r i v e / H e a d R e g .
1 1 S t a t u s R e g .
C o n t r o l B l o c k R e g i s t e r s
1 0 A l t . S t a t u s R e g .
1 1 D r i v e a d d r e s s R e g .
D I O W = 0 ( W r i t e )
D a t a R e g .
F e a t u r e s R e g .
S e c t o r c o u n t R e g .
S e c t o r n u m b e r R e g
C y l i n d e r l o w R e g .
C y l i n d e r h i g h R e g .
D r i v e / H e a d R e g .
C o m m a n d R e g .
D e v i c e c o n t r o l R e g
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Specification