.. How
to
Use
RAM CHECKER
Insert
RAM
CHECKER into BOOT
ROM
socket and turn
the
power on. Then
RAM
TEST·1 and
RAM
TEST-2 will automatically
be
carried
out
from
RAM
address
$0000
to
address $F FFF
as
shown below
and.the tested results will
be
displayed.
The checker tests
the
store by dividing
it
into two parts of addresses $0000
to
$7FFF
and
$8000
to
$FFFF.
Example
of
the
test results (When all RAM'. are normal)
Check
RAM
(l)
block, 16K bytes,
RAM
(ll) block 16K bytes
1)
RAM
TEST·1
A writelread test of data $00 and
$FF
is
carried
out
from address
$0000
to
$FFFF,
and
if
an error
occurS ERROR
is
displayed
in
the
16K bytes unit.
Example
of
above mentioned display
IOOOOi'::
O
.
K
.
I
....
·
Result of writehead test from address
$0000
to
$3FFF
is
normal.
,_J
_:.
'~11'
Example of display when ERROR appearS.
I ER:23,5B:00,
01
1...........
Write
in
data was
$00
at
address
$2358
but
read·out data
was
$01.
An
error
is
displayed by
the
address
number
at
which
the
error takes place, and
the
excution
of
check
is
stopped
at
the
address.
2)
RAM
TEST·2
Write/read
test
is
carried
out
with
the
following items_
al
Write-in data $00 (From address $0000
to
$7FFF)
b)
Write-in data
$FF
(From address $0000
to
$7FFF)
c)
Write·
in
data
$00
(From address
$7FFF
to
$0000)
d)
Write-in data
$FF
(From address
$7FFF
to
$0000)
e)
Write-in data
$FO
and
$OF
entered alternately (From address $0000
to
$7FFF
and vice verSa.)
f)
Write·in data
$00
(From address
$8000
to
$FFFF)
g)
Write-in data
$FF
(From address
$8000
to
$FFFF)
hi Write-in data
$00
(From address
$FFFF
to
$8000)
i)
Write-in data
$FF
(From address
$FFFF
to
$8000)
j) Write-in data
$FO
and
$OF
alternately (From address
$8000
to
$FFFF
and
vice
versa)
Example
of
ERROR in
RAM
TEST·2
,
.RAM TEST-2
00
FF
00
ER·23FF·01
Test results of
a)
and
b)
were normal
but
in
c), although data
$00
was
written in address $23FF, read-out
data
was
$01. When ERROR
is
displayed
in
the above mentioned
RAM
TESTs, decide which
RAM
block
is
bad according
to
the
memory
address where
the
error occurs. Then
you
can decide which
RAM
is
bad in the
RAM
block where
the
error occurs by
the
bytes
pattern
of
the
write-in data and reao-out data.
In
the
above
example, you can tell
that
it's
RAM
(I) block by
$23FF
and
that
RAM
1
is
bad because write-in data
is
$00
but
read-out
data
is
$01.
(See
Fig.
next)
t~'
06
05
04
03
02
01
DO
-------
Write·in date
$00
0
0
0
0
0
0
~Error
Read-out data
$01
0
0
0
0
0
0
:,:
':
l:
:
..
i
to
occur
-14-
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