Specifications
The
precise power requirements
of
the Little
Board/PC
depend
on
a
number
of
factors,
including what functions are present
on
the board, whether the SCSI bus
is
terminated, and
what peripherals are connected to the board's
I/O
ports. For example, PC keyboards draw·
their power from
the
keyboard connector
on
the board, thus add to the total power drawn by
the board from its power supply.
Similarly, boards connected to the PC Expansion Bus may
draw their power through the Little
Board/PC.
Table 2-3 gives the typical power consumption
of
the standard configurations
of
the Little
Board/PC. All versions shown in the table include both serial ports, the printer, speaker, and
keyboard ports, the floppy disk controller, and the
PC
Expansion Bus.
Note that the
SCSI bus terminators consume approximately
.8
watts of power by themselves;
the power values shown
in
Table 2-3 include the SCSI terminators when
the
configuration
includes the
SCSI interface logic.
Table 2-3. Power Consumption vs. Configuration
WITH
SCSI
LOGIC
WITHOUT
SCSI
RAM
(*)
CURRENT
POWER
CURRENT
POWER
256K
649
rnA
3.3
W
449
rnA
2.3 W
512K
691
rnA
3.5 W
491
rnA
2.5 W
768K
734
rnA
3.7
W
534
rnA
2.7
W
(*)
Assunes
113-chipll
SIMMs
2.3 ONBOARD OPTIONS
This section includes the onboard device options which can
be
added to the Little Board/PC.
These include
DRAM
and
byte-wide memory devices, nonvolatile
RAM
cartridges, a
real
time clock module, and a variety
of
onboard expansion MinModules including the
Ampro
MiniModule video controllers.
2.3.1 DRAM Memory
Jumper
pairs W42-W44 must
be
set to correctly indicate the
amount
of
onboard SIMM
DRAM
memory which is to be utilized.
Note that the configurations which utilize onboard memory above
640K are only usable under
special circumstances. These
are
the restrictions which govern the use
of
memory above
640K:
•
Do
not
jumper
for
more
than
640K
if
a
CGA,
EGA,
or
VGA-compatible
video
controller is in use.
•
Do
not jumper for more than 704K
if
an
MDA
or
Hercules-compatible, video controller
is
in use. This includes the Ampro MiniModule/CGA in monochrome mode.
Generally speaking, the 768K memory configuration is only usable when the
DOS
display
device
is
rerouted to a serial port, as discussed in Chapter 3. Also observe the following note
if
you plan to use
768K:
2-5