Philips CDI 220/31 - Page 15

If error,
display: 5 Er09
5.
write inverted pattern to nvram
6.
read byte from nvram
and
compare with pattern
7.
if
byte
read
is
ok
then restore original byte
else give error message and stop testing
If
error,
display: 5 Er10
8.
repeat this for every possible nvram address.
STEP 6-8 : DRAM
The dram test is always a destructive test. The test is
performed for
both
ram
chip1
and chip2 as one large
memory followed by a test for each bank separately.
On
the displays following, the 'x' is a memory counter. The
counter is incremented every 256k.
So
for the full range it
counts from 1
to
4.
STEP 6A : TEST THE FULL DRAM MEMORY
The following actions take place
in
this test:
1.
fill the memory with the long word address as data.
display: 6AFx
2.
read
the memory contents and compare with the
address.
display: 6ARx
3.
if
the
long word read is
ok
then continue
else give error message and stop testing.
If
error,
display: 6ArxEr11
STEP 6B : TEST THE FULL DRAM MEMORY WITH
INVERTED DATA
The following actions take place
in
this test:
1.
fill the memory with the inverted long word address
as data.
display: 6BFx
2.
read the memory contents and compare with the
inverted address.
display: 6BRx
3.
if
the long word read is
ok
then continue
else give error message and stop testing.
If error,
display: 6BrxEr12
STEP
7A:
TEST DRAM CHIP1
The following actions take place
in
this test:
1 . fill the memory with the long word address
as
data.
display: 7AFx
2.
read the memory contents and compare with the
address.
display: 7ARx
3.
if the long word read is ok then continue
else give error message and stop testing.
If
error,
display: 7ARxEr13
STEP
7B:
TEST DRAM CHIP1 WITH INVERTED DATA
The following actions take place
in
this test:
1.
fill
the
memory with the inverted long word address
as data.
display: 7BFx
2.
read the memory contents and compare with the
inverted address.
display: 7BRx
3.
if
the long word read
is
ok then continue
else give error message and stop testing.
If
error,
display: 7BRxEr14
STEP BA: TEST DRAM CHIP2
The following actions take place
in
this test:
1.
fill the memory with the long word address as data.
display: 8AFx
2.
read the memory contents
and
compare with the
address.
display: 8ARx
3.
if the long word read is ok then continue
else give error message and stop testing.
If
error,
display: 8ARxEr15
PCS
67
640