Specifications
7.1
IDLE
LOOP
After
successful
completion
of
the
Powerup
code,
the
68000
continuouslY
loops
on
a
modified
version
of
the
same
code
until
the
user
either
lo~s
in
or
enters
Maintenance
Mode.
If
Idle
Loop
fails
a
test,
it
does
not
do
an~
more
testins
until
the
next
pass.
All
errors
are
lo~~ed
to
the
host,
but
onl~
the
first
error
detected
is
reported
to
the
Mother
Board
and
Keyboard
LED's.
The
followinS
tests
are
executed
durin~
Idle
Self-Test:
1.
68000
CPU
(extended)
2.
ROM
Checksum
3.
Pro~ram
Memory
(truncated)
4.
Vs~nc
Vector
Time-Out
5.
Frame
Buffer
Memory
(truncated)
6.
BBA
Scratchpad
Memory
7.
Keyboard
ID
Between
tests,
Idle
Loop
polls
for
mouse
buttons
(in
which
case
the
host
is
informed),
host
commands
(in
which
case
we
branch
to
the
command
loop),
and
control/shift/f4
(in
which
case
we
branch
to
maintenance
mode).
After
a
mouse
button
is
hit,
we
initialise
a
counter
and
inc-
rement
it
durin~
ysync
for
five
seconds.
Between
tests,
we
check
this
fla~
to
make
sure
the
five
minuts
are
not
UP.
If
we
have
not
received
a
command
from
the
host
in
that
time,
and
link
is
available,
we
can
assume
the
host
is
dead
in
the
water
and
put
the
Link
Down
icon
UP
on
the
screen.