Specifications
5.6
SCSI INTERFACE
The
53C80
SCSI
Protocol
Controller
device, which
generates
the
board's
SCSI interface,
contains eight readable
and
eight writable registers, which
begin
at
the
base address
of
330h.
The
53C80's internal registers
are
shown in Table 5-5.
Table
5-5.
53C80 Internal Reglst
....
I/O
ADR
INPUT/OUTPUT
FUNCTION
0330h
Inp.lt
Current
SCSI
Data
0331h
Inp.lt
Initiator
Command
Register
0332h
Inp.lt
Mode
Register
0333h
Inp.lt Target
COIIIII8nd
Register
0334h
Inp.lt Current
SCSI
Bus
Status
0335h
Inp.lt
Bus
& Status Register
033611
Inp.lt Inp.lt
Data
Register
0337h
Inp.lt Reset
Parity/Interrupt
Command
0330h
OUtput
OUtput
Data
Register
0331h
OUtput
Initiator
Command
Register
0332h
OUtput
Mode
Register
0333h
OUtput
Target
Command
Register
0334h
OUtput
Select Enable Register
0335h
OUtput
Start
DNA
Send
Command
033611
OUtput
Start
DNA
Target Receive
Command
0337h
OUtput
Start
DNA
Initiator
Receive
The SCSI interface has a wide variety
of
applications, including:
•
Use
with SCSI disk, tape, optical drive controllers, and
other
SCSI devices
•
Use
as a
bidirectionalI/O
port
The
Ampro
SCSI/BIOS
and
SCSI
Support
Software provides
SCSI
support
for "generic
SCSI"
random
access devices (i.e.
hard
disk controllers
and
drives),
which
use
the
SCSI
"Common
Command
Set."
So
that you can use SCSI devices
and
functions
not
supported
by
the
standard
Ampro
drivers
and
utilities,
a
function
has
been
included
in
the
Ampro
SCSI/BIOS
which
can
be
accessed through
an
extension of
the
INT
13 support. This is dis-
cussed below.
If
you plan
to
program the SCSI interface directly, you will probably require copies
of
both
the
NCR
5380-53C80 SCSI Interface Chip Design Manual
and
the
ANSI X3.131 SCSI specifi-
cation.
Sources for
both
of
these documents are referenced
in
the
beginning
of
Chapter
4.
5.6.1 SCSI
Programming
When
using
the
SCSI interface with SCSI disk controllers
and
drives, special programming is
not
generally required;
the
Ampro
SCSI/BIOS
and
SCSI Support Software drivers
and
utili-
ties accommodate many types
of
disk controllers
and
disk drives. Installation
of
the
hard
disk
software
is all
that
is
generally
required,
providing you
are
using
controller
and
drive types
supported. (Refer
to
Chapter
3.)
When
using the
53C8O
in
SCSI applications, care must
be
taken
to
meet
the
specified timing
constraints.
For
detailed
timing
information, consult your
peripheral
controller's
technical
manual,
and
the
ANSI SCSI specification referenced above.
5-7