Reflex Lexicon - Page 23

Performance
Verification
Lexicon
DRAM
Test
(6)
The DRAM
test
is
a little different
than
the other memory
tests
because the
Z80
does not
have
direct
access
to
the actual
DRAM.
The only
way
the Z80
{U12)
can read
from
or
write
to
the
DRAM
(U38-41
or
U20-23)
is
through
the
Lexichip.
The
Lexichip II
has
6
internal
register locations through
which
the
Z80
can
read and
write
data
to
the digital
audio
bus.
A
special
microcode
program
is loaded
into
the
Lexichip
to
run
the
test.
While
the
test
is
running,
the
letter
r
is displayed
to indicate that the
test is
running. The
testtakes
approximately
1
3 seconds
for
64K DRAM
,
50 seconds
for 256K
DRAM
and
4
minutes for
1 MEG
DRAM. The first thing
that the
DRAM
test does
is
determine
the size of
the DRAM.
The
current
software
expects the
DRAM
to
be
either 64K, 256K,
1
MEG
or
4
Meg RAMs.
If
a failure
occurs,
the
diagnostics
may indicate
which
DRAM(s)
is
at fault.
The
display
will flash
an error
code
in
hexadecimal
from 1-F
four
times
after
the
PRESET/REGISTER
button is pressed.
Below
is
a
table
illustrating which
DRAM(s)
are
associated with
each
error
code.
Display:
HEX)
Decimal
4464
DRAM
1
1 U20
2
2 U21
3
3 U20,
U21
4
4 U22
5 5
U20, U22
6
6 U21,
U22
7
7
U20, U21, U22
8
8
U23
9
9 U20,
U23
A
10
U21,
U23
B
11
U20, U21,
U23
C
12
U22, U23
d
13
U20, U22,
U23
E 14
U21, U22, U23
F
15
U20, U21, U22,
U23
The
following
error
codes
are
used
when
using the View Previous
Test and
Results Tool
(Test
14);
1
5555
test
2
AAAA
test
3
Address
Test
(address
is
written
into the memory)
Burn-In
Test
(7)
This
is
a
diagnostic
sequencing
utility
that
continuously runs
the following
tests,
until
a test
fails,
or
power is
removed from
the unit.
ROM
Test
(5)
SRAM
Test
(2)
WCS
Test
(3)
Interrupt
Test
(4)
DRAM
Test
(6)
If
a
test
fails
the
-
sign
is
displayed.
To find
out
what
test
failed,
press any
front
panel
button to display the
test number as shown in
parenthesis
next
to
the
test
above.
3-10