Specifications
2.6
PC
EXPANSION BUS -
J8
A
PC
compatible expansion
bus
appears
at
connector
J9, except
that
it is
brought
out
to
a
healkr
COMeCtor,
rather
than
edgecard connectors.
The
board's
PC
Expansion Bus connects
to
the
ftrst 62 pins
of
J9;
the
two additional pins
of
J9
(A32, B32) offer additional ground signals, for enhanced system reliability.
PC
Expansion
Bus connector pinouts
are
given later
in
this chapter.
Table 2-25 shows the pinout and signal functions
of
the
signals
on
the
board's
PC
Expansion
Bus and MiniModule headers. Further information about these signals is available
in
numer-
ous pUblications, including
the
IBM technical reference manuals for
the
PC
computer,
and
from the reference documents listed
in
the
beginning
of
Chapter 4.
Note that
the
board's
PC
Expansion Bus
and
MiniModule connector pins
are
numbered dif-
ferently
from
the
other
header
connectors
on
the
board,
so
that
they
correspond
to
the
scheme normally used
on
the
PC
Expansion Bus. Speciftcally, rather
than
being designated
numerically (1,
2,
3, etc.) the signals
of
the
PC
Expansion Bus
are
designated
aJp/ul-numericaJ-
{y
(A!,
A2,
"'J
Bl,
B2, ... , etc).
PC
Expansion Bus signals
are
buffered
on
the
board
and provide approximately 4
mA
source
and
sink currents for peripheral cards, with
TIL
compatible signal levels
at
a logic
'ow"
level
of
0.4 Volts.
2.6.1 Onboard MiniModule Header and Bus Expansion
An
important feature·
of
the
Little
Board/PC
is its onboard MiniModule header. A header
connector
at
19 provides a
PC
Expansion Bus interface for use with one
of
Ampro's
3.6"
x
3.8"
expansion MiniModules.
When
installed
on
J9,
the
onboard expansion module ftts within
the
Little
Board/PC's
space envelope.
The
onboard
expansion module provides a
bus
pass-
through
connector, allowing additional external bus expansion when the module is installed.
Several options
are
available for mounting multiple MiniModules
on
the Little
Board/PC:
•
Stacker/MM
-- Allows two MiniModules
to
be
stacked
together
and
mounted
as a
single
unit.
•
StackPIane/MM
-- Provides two expansion bus header connectors for mounting Mini-
Modules
on
a Little Board form-factor board.
When
used with
the
Stacker/MM,
up
to
four MiniModules
can
be
attached.
The
SSD Expansion board
also
offers two expansion
bus
header
connectors for mounting MiniModules.
Ampro
currently offers several display coQtroUer MiniModules which offer a wide variety
of
standard
PC
and
AT
video modes, including VGA,
EGA,
CGA, MDA,
and
Hercules display
compatibility,
on
CRT
monitors,
LCD
panels,
and
electroluminescent
(EL)
panels.
Ampro
also
offers
additional
MiniModules,
including
serial/parallel
interfaces,
modems,
etc.
Contact
Ampro
for information
on
additional MiniModules.
2-26