Specifications
Table 5-6. Jumper Input Port
Bit
7
6
5
4
3 2 1 0
HSI
W29
W28
W27
W26
W25
W24
W23
Bit
Si gnal/FU'lCt i on
7
HSI
- Handshake
input
signal
for
the
V40
Serial
Port.
Must
be
polled
by
software
if
active
input
handshaking
is
required.
Can
be used
for
CTS,
OCD,
or
other
desired
purpose.
3-6
W26.27.2B.29
- These
four
bits
reflect
the
states
of
the
c:orresponding
j~r
positions.
A
j~r
"on"
results
in
the
data
bit
being a
"0",
while
"off"
results
in
a
"1."
These
bits
are
normally
used
by
the
ROM-BIOS
to
determine
the
type
of
floppy
drives.
0-2
W23.24.25
- These
three
bits
reflect
the
states
of
the
c:orresponding
j~r
positions.
A
j~r
"on"
results
in
the
data
bit
being a
"0",
whi
le
"off"
results
in
a "1."
These
bits
are
normally
used
by
the
ROM-BIOS
to
determine
the
board's
SCSI
Initiator
10.
5.6.4 Ampro SCSI/BIOS
To make it easy to use SCSI devices and functions not supported by the standard Ampro
drivers and utilities, functions have been included in the board's
ROM-BIOS which allow the
use of the
SCSI interface without the need for direct hardware programming. This support
is
accessed through
an
extension
of
the INT
13
ROM-BIOS support, and is known as the
Ampro
SCSI/BIOS.
The Ampro SCSI/BIOS adds an additional layer of standardization to SCSI, by providing a
high level interface for software that eliminates the need
for
direct programming of the SCSI
bus interface hardware. This standard software interface is accomplished through
an
exten-
sion to the
!NT
13
support normally provided in a PC ROM-BIOS for hard disk access. SCSI
drivers and utilities written around the Ampro SCSI/BIOS INT
13
extensions will run on any
system in which the INT 13 extensions are available. (This includes all
of
Ampro's DOS
compatible Little Board
single
board
syst£ms.)
Detailed information
on
the SCSI/BIOS functions provided within the Little
Board/PC
ROM-BIOS
is
available in application note AAN-8804, available from Ampro.
If
you plan to support SCSI devices using the SCSI/BIOS, you will probably need to become
acquainted with the
SCSI bus and its protocols. To obtain a copy of the ANSI SCSI specifica-
tion, contact the American National Standards Institute referred to previously in this chapter.
5-9