Test Types - Kurzweil K2000 Service Manual

SECTION
4
DIASSO_4.DOC
12/22/92
will be interrupted and hold temporarily and will resume when any front panel
button
is
pressed.
As the continuous tests are running, the
bottom line
of the display will
indicate the number of tests that have been completed, and the number of
failures that have occurred.
4
.
13 TEST TYPES
The tests described in this section are of three types, referred
to
as
RAM
tests, ROM
tests, and I/O tests.
Memory
tests check the physical
memory
addresses of the data corresponding
to various components.
This
is done by
writing
an arbitrary test data pattern
to
memory and reading
it back,
comparing the written data
to the read data.
ROM tests involve comparing
the
data stored in the ROM components to
a
checksum.
I/O tests also send
a
test
data pattern from the central processor to the component
(s)
being
tested, and
check whether the data are being exchanged properly between the central
processor and the tested component
(
s
)
4.13.1
Memory
tests
There are two stages
to
a
memory
test: the data
test, and the address
tfest.
In the data test,
a
test data pattern
is
written from
the processor
to the
memory component being
tested. The diagnostic software expects the data
pattern that's written
to memory
to be read back exactly
as it was written.
If this is the case, the test
passes.
If the observed data
(the
data read
from memory) differ from the expected data
(the
data written
to memory)
,
the
test fails.
When
a
data failure occurs,
it is
displayed
in the following
format: the
memory address where
the failure occurred; the
expected hex value
at that
address; the actual observed value at that address.
See Figure 4.5 for an
example
Test Item
2
Please
wait- Testing.
.
.Data Err
Pddress
2
00000000
Expected
2
00000000
^0bserued2 00000000
Press anykey to continue-
Figure
4.5. Data Failure
In the
address
test, the central processor
(CPU-a
Motorola
68301) checks every
memory address related
to
the component being tested.
A
test data pattern
is
written
to each address, and then read back.
The diagnostic software expects
the data pattern
to be read back from the same address to which it was sent.
If the observed address
(the address read
from)
matches the expected address
(hhe
address written
to)
,
the test passes.
If the observed address does not
match
the expected address, the test
fails. Address failures are displayed
14