Reflex Lexicon - Page 22

Reflex Service
Manual
Performance
Verification
SRAM
Test
(2)
This
is actually several
tests
that
get
performed on the
SRAM {U9)
in the
system.
First,
the
RAM
is
filled with
the value
55
hex
(01
01 01 01
binary),
then
each
memory
location
is
read
to see
if
it contains
55.
If
55
is
in
the memory
location,
the location is
filled with AA
hex
(1010
1010
binary), and the next
location is
processed.
Once the
RAM
has
been
checked for55’s and
filled with
AA’s,
the process
is
repeated,
checking for AA’s
and storing
O’s.
Then, the
memory
is checked for
O’s
and the
test
exits.
The following
error
codes
are
used
for
this
test:
1
55 test
2 AA
test
3
00 test
WCS Test
(3)
The WCS
test is identical
to
the
SRAM
test
except
that
it is
run
on the
program
memory
space
in
the
Lexichip
2
(U14).
The following error
codes are used
for
this
test:
1
55 test
2 AA
test
3 00 test
Interrupt Test
(4)
This
test
verifies
that the
NMI
Interrupt
is
working,
and that
it occurs at the
proper intervals.
The
interrupt
is
allowed
to run
for
a
period of
time that should
allow
20
interrupts. A
count
of
the
interrupts is kept and compared
for
overshoot
and undershoot.
More
than 21
interrupts means the interrupt is
too
short. Fewer
than
19 interrupts
means it’s
too
long.
Note that the User
Diagnostics
allow
you
to
distinguish overshoot and
undershoot.
The
following
error
codes are
used
for
this
test:
1
Interrupt
count
was <1
9
over
a
period of
1
0.24ms. Too
slow
or
dead.
2
Interrupt
count was
>22
over
a
period of 1 0.24ms. Too fast.
ROM
Test
(5)
This
is
a
checksum
test
of
the
system
ROM
(U8).
A
checksum
test
is
performed
by
reading
each memory
location
in ROM
and adding the stored
value
stored.
This
number
is
compared with the total
calculated
when the
software was first
assembled.
A
mismatch
indicates
a
problem with the
ROM
or with
the
ZSO’s
(U12)
ability
to
read the
ROM
(shorted address line,
etc...).
The
last
two
memory
locations are
reserved
to
store
the
comparison value.
In
practice, the
ROM
test
is
primarily
useful
for
verifying
that the contents of
the
ROM
were transferred correctly from
the master
and are uncorrupted.
The
number
1
(failed)
is the only error
code
available
for
this
test.
3-9