Sage II - Delay Line Mods

SAGE rr
SERVICE MANUAL
[1.0]
ERROR
LOOKUP
LIST
EXCEPTION
ERRORS
XVIII"03 EXCEPTION
BRRORS :
These errors are
generally
caused by software
problems
except for
RAM
parlLy
errors.
Wtren
processlng
an
exceptlon error, lnterrupts
are turned
off and the
BIOS
ls
dlsabled,
unless the
user
has re-directed
the
error to hts
own
error handling
routlne"
Non user-intercepted
errors have
thls format:
EXCEPTION:
(error
type)
'Error
at'
<8
digit location)
Error
types
are
deflned:
tsus
Error
fhe
processor
trled to
read
memory
and there
was no response.
Memory
may not
exist.
A
hardware
strapping
option
deterrnlnes
what
memory 1s equipped.
Additional
lnformatlon
1s displayed:
ttFunction:xxxx
Access :xxxxxxxx
Instr
:xxxxtt
Function
a-2 .
30
4.
Access
Tns tr
is a
4 digit word
with
blts
set:
.are the
state
of
the
processor
functlon
code outputs FCO,FCl
and FCz
.is
0
for
an lnstruction,
I
for
not
an
instructl-on.
.ls
0
for write,
I
for
read.
ls
the
8
diglt address
of
ls
the
4 dlgtt
lnstructlon
the
attempt.
word
executed
Bus
error
on TIUE
OUT A bus
tirne out error
ls
caused
when
AS-
stays
1ow for
longer
than
16
usec,
Thls is
caused
by
either
a
software
or
hardware
condltlon
whlch
prevents
DTACK-
from
being
applted
withln
16
usec.
U3,
a
74LS390
dual decade
counter is
used
to
count cycles
of the
500
Khz clock,
the
QD
output of
the
counter
ls
fed
through
U7,
an
open
collector
invertlng
buffer
to the
BERR- lnput
to
the
processor.
AS- is
applied
to the
clear
input
causlng
the
counter to
be
cleared whenever
AS-
is
inact
ive
.
hlhenever
AS-
goe
s ac
t
ive
(
low)
the
counter
starts
counting and
if
AS- has not
been
removed
by the
Sttr
count,
QD
goes
hlgh
generating
a
bus
error
slgnal.
75