GMX Micro-20 68020 User guide

· .
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GMX
!Ucro-20-
68020
S
ingl.e-b::lard
Computer
Hardware
Setup
ttanua1

GMX
t!1cro-20-
68020
Singl.e-board
Computer
COPYRIGHT
-1986
GtIX
Inc.
Hardware
Setup
Kanual.
1337
W.
37th
PLace
Chicago.
XL
60609
312-927-5510
*
TWX
910-221-4055
All
Rights
Reserved
Reproduction
of
this
aanual..
in
whol.e
or
part.
by
any
aeans.witbout
express
written
permission
froa
GMX
Xnc.
isstrictl.y
prohibited.
G~
1s
a
trademarks
of
GMX
:mc.
Chicago.
XL
60609

GMX
Micro-20-
Hardware
setup
Manual
Revision
History
Revision
A
01/13/86
First
general
release
<§>1986
GMX
INC
ii
Rev
A

GMX
Micro-20·
Hardware
setup
Manua~
CONTENTS'
CHAPTER
1
HARDWARE
SETUP
SECTION
PAGE
1:
POijER SUPPLy
•••••••••••••••••••••••••••••••
1
2:
-SERIAL.
ADAPTER
BOARD
•••••••••••••••••••••••
1
3:
SYSTEM
CONSOL.£
TERMINAL.
3-1:
Conso~e
Termina~
Requirements
•••••••••
1
3-2:
Conso~e
Termina~
Connections
••••••••••
1
3-3:
Conso~e
Baud
Rate
Se~ection
•••••••••••
2
3-4:
Conso~e
Termina~
Data
Format
••••••••••
3
4:
RESET
and
ABORT
SWITCHES
•••••••••••••••••••
3
5:
REMOTE:
INDICATOR L.£Ds
••••••••••••••••••••••
3
6:
DIP-SWITCH OPTIONS
•••••••••••••••••••••••••
3
7:
JUMPER OPTIONS
•••••••••••••••••••••.••••••••
4
8:
FLOPPY DISK DRIVES
8-1:
F~oppy
Disk
Drive
Requirements
••••••••
5
8-2:
F~oppy
Disk
Drive
Conriguration
•••••••
5
8-3:
F~oppy
Disk
Ready
Option
••••••••••••••
5
8-4:
F~oppy
Disk
Drive
Connections
•••••••••
6
9:
SASI
INTERFACE
9-1:
SASI
Contro~ler
Requirements
••••••••••
6
·9-2:
SASI
Control~er
Conriguration
•••••••••
7
9-3:
SASI
Contro~~er
Connections
•••••••••••
7
10:
PARALr.EL.
INTERFACE
10-1:
Para~le~
Interrace
Requirements
•••••••
7
10-2:
Para~~el
Interrace
Conriguration
••••••
8
10-3:
Para~le1
Interrace
Option
Jumpers
•••••
8
(con't)
01986
GMX
INC
iii
Rev
A

SECTION
CHAPTER 2
SYSTEM
CHECKOUT
11:
Hardware
Diagnostics
PAGE
11-1:
Initial
Power-up
••••••••••••••••••••••
9
11-2:
Confidence
tests
••••••••••••••••••••••
9
11-3:
020Bug
Diagnostics
•••••••••••••••••••
10
11-4:
Self
test
Loop
Mode
•••••••••••••••••••
11
APENOICIES
Appendix
A:
DC
Power
Connector
P8
•••••••••
13
Appendix
B:
Switch
and
LED
Connections
••••
14
Appendix
C:
Connector
and
Jumper
Locations
15
_1986
GMX
INC
iv
Rev A

INTRODUCTION
This
manua1
contains
genera1information
ori
the
initia1
setup
and
and
checkout
of
the
GMX
Micro-20
SingLe-board
Computer
when
used
with
the
GMX
Micro-20
Support
ROM
firmware
and/or
one
of
the
optionaL
disk
operating
systems.
It
is
intended
to
be
used
in
conjunction
with
the
"GMX
Micro-20
Hardware
Reference
ManuaL"
(for
connector
pinouts,
etc.)
and
the
appropriate
software
manua1s.
The
manuaL
is
divided
into
·two
chapters.
Chapter
1
dea1s
with
basic
hardware
requirements
and
configuration.
It
is
intended
primariLy
for
users
who
have
purchased
the
GMX
Micro-20
board
for
use
with
their
own
power
suppLy,
disk
drives,
etc.,
a1though
the
information
on
cons01e
termina1
requirements
appLys
to
a11
users.
Chapter
2
covers
initia1
system
checkout
using
the
buiLt-in
diagnostic
firmware.
We
recommend
that
811
users
become
fami1iar
with
the
buiLt-in
diagnostics,
and
that
the
diagnostics
be
used
during
initia1
system
setup
to
verify
proper
operation
of
the
board.
If
you
have
any
questions
or
comments
concerning
the
setup
and
operation
of
the
GMX
Micro-20
or
the
information
in
this
manuaL,
pLease
contact
us
at
the
address
or
phone
number
1isted
on
the
cover
page.
mlq96
GMX
INC v
Rev
A


CHAPTER
1
HARDWARE
SETUP
,
This
chapter
covers
the
basic
hardw~re
requirements
for
operating
the
GMX
Micro-20
with
020Bug
and/or
a
disk
operating
system.
Refer
to
appendix
C
for
the
locations
of
connectors
and
jumper
areas.
SECTION
1:
POWER
SUPPI..Y
The
board
requires
a
source
of
well
filtered
and
regulated
+5
and
+12
Volts
D.C.
Connect
a
suitable
supply
to
D.C.
power
connector
P8.
which
uses
the
same
mating
connector
and
pinout
as
a
standard
5
1/4"
disk
drive.
Appendix
A
shows
the
pinout
of
connector
P8.
SECTION
2:
SERIA[.
ADAPTER
BOARD
The
serial
adapter
board
provides
line
drivers
and,
if
needed,
the
appropriate
additional
supply
voltages
to
convert
the
TTL
level
signals
on
the
GMX
Micro-20
board
to
match
an
interface
standard
such
as
RS-232.
A
50-pin
ribbon
cable
connects
the
adapter
to
the
main
board
at
connector
P2.
Be
sure
to
observe
proper
porarity
(pin
1)
when
connecting
the
s~rial
adapter
board.
CAUTION:
In
most
Micro-20
serial
terminals.Severe
signals
(such
as
cases.
an
adapter
board
MUST
be
used
between
the
GMX
I/O
connector
(P2)
and
external
devices
such
as
damage
to
the
board
will
result
if
non-TTL
level
RS-232)
are
connected
directly
to
connector
P2.
Refer
to
the
"Hardware
Reference
Manual"
and
the
serial
adapter
board
manual
for
more
information.
SECTION
3:
SYSTEM
CONSOLE
TERMINAI..
3-11
Console
Terminal'Requirements
At
least
one
standard
ASCII
serial
terminal
must
be
connected
to
the
board.
Additional
terminals
may
be
connected;
however,
for
initial
operation
only
the
console
terminal
is
required.
The
console
terminal
must
be
configured
for~_~51.tt"t:.J,8).c:\Clta
bi~s,
~~c~,J2..~r:l,'ty
(bit
8
always
0).
and
9DJ~~B~,:t.
The
terminal
baud
rate
must
be
set
to
19,
200!,J
9._
2Kl..",.~~d
unless
the
default
baud
rate
of
the
Support
ROM
has
been
changed.
"Refer
to
the
section
on
console
baud
rate
selection
for
information
on
changing
the
default
baud
rate.
The
Micro-20.
3-2:
Console
Terminal
Connections
console
terminal
connects
to
serial
port
#0
on
the
GMX
If
the
standard
25-pin
RS-232
adapter
board
is
used,
port
~1986
GMX
INC
-1-
Rev_
A

#0
is
accessed
at
connector
P1
on
the
adapter.
P1
on
the
25-pin
adapter
is
wired
as
DCE:
and
a
"straight"
3
or
4
wire
cabl.e
can
be
Used
to
connect
the
terminal..
If
a
different
serial.
adapter
board
is
being
used,
r~fer
to
the
adapter
board
documentation
for
connector
l.ocation
and
pinout.
In
many
cases,
onl.y
transmit
data,
receive
~ata.
and
signal.
ground
are
required.
However.
handshaking
wil.l
·be
needed
if
the
terminal
is
not
capabl.e
of
continuous
data
reception
at
the
baud
rate
being
used.
The
CTS
handshake
input
can
be
used
to
start
and
stop
output
from
the
GMX
Micro-20
to
the
terminal..
When
CTS
is
asserted
(high),
output
is
enabl.ed.
when
CTS
is
deasserted
(l.ow),
output
is
disabled.
The
software
also
supports
XON/XOFF
(OC1/OC3)
handshake
for
both
input
and
output.
If
XON/XOFF
1s
used,
hardware
handshake
1s
not
required.
3-3:
Console
Baud
Rate
Selection
The
default
console
baud
rate
is
19,200
(19.2K)
baud.
If
the
console
terminal
is
not
capable
of
operation
19.2K
baud,
the
Support
ROM
must
be
altered
to
change
the
default
baud
rate.
A
one-byte
value
in
the
ROM
determines
the
default
baud
rate
for
the
console
terminal
used
by
the
ROM
firmware
and
optional.
disk
operating
systems.
The
baud
rate
byte
is
the
fifth
byte
(address
$0004)
1n
PROM
#4
of
the
PROM
set.
PROM
#4
is
located
at
U-13
on
the
GMX
Micro-20
board
and
contains
the
8
high-order
data
bits,
024-031.
The
PROMs
are
normal.ly
shipped
with
byte
5
set
to
all
ones
($FF).
This
'is
the
unprogrammed
state.
so
any
desired
value
can
be
programmed
at
this
location
without
reprogramming
the
entire
device.
To
change
the
default
console
baud
rate,
locate
the
desired
rate
in
the
tabl.e
(Figure
3-1)
and
reprogram
the
PROM
with
the
value
shown
in
the
table.
If
PROM
programming
facil.ities
are
unavailable.
contact
the
factory
for
information
on
obtaining
custom
PROM
sets.
CONSOLE TERMINAL DEFAULT BAUD RATE BYTE
BAUD RATE BYTE BAUD RATE BYTE
75
$00 1800
$AA
110 $11
2000
$77
134.5 $22
2400
$88
150 $33
4800
$99
300
$44
-9600
$BB
600
$55
19,200
SCC
1200 $66
Flgure3'-1
<e1986
GMX
INC
-2-

3-4:Conso1e
Data
Format
The
cons01e
POrt
is
configured,
by
default,
to
the
fo110wing
transmission
format:~_Q.C!1:a,pi1:~,
sPC:l~ep?r~ty
(bit
8
is
a1ways
zero),
and],
~t;9.P"p1t.
All
of
the
software
uses
this
format
for
the
cons01e
termina1.
The
transmission
format
for
the
cons01e
port
is
fixed,
and
can
not
be
modified
by
the
user.
The
other
three
ports
also
default
to
this
format,
but
can
be
changed
if
necessary.
SECTION
4:
RESET
and
ABORT
SWITCHES
The
board
has
provisions
for
connecting
remote1y
mounted
reset
and
abort
switches.
The
reset
switch
resets
the
processor,
and
any
other
devices
connected
to
the
processor's
reset
line.
The
abort
switch
generates
a
1evel
7
autovector
interrupt
to
the
processor,
and
is
genera11y
used
during
software
debugging
to
interrupt
a
running
program.
The
abort
switch
also
functions
as
a
sing1e-step
switch
when
the
hardware
single-step
mOde
is
enab1ed.
Appendix
B
shows
the
necessary
connections
for
reset
and
abort
switches.
See
the
"Hardware
Reference
Manual"
and
the
software
documentation
for
more
detai1ed
information
on
switch
functions.
SECTION
5:
REMOTE
INDICATOR LEOs
The
board
has
provisions
for
remote
mounting
of
a
HALT
LED
,
and
an
LED
for
power-on
indication.
The
remote
HALT
LED
duplicates
the
function
of
the
on-board
HALT
LED
(LED
1),
while
the
power-on
LED
provides
an
indication
that
+SVDC
is
app1ied
to
the
board.
There
are
no
provisions
fora
remote
status
LED
(LED
2);
however,
one
can
be
provided
by
removing
the
on-board
LED
and
wiring
a
remote
LED
direct1y
to
the
board.
Appendix
B
shows
the
necessary
connections
Refer
to
the
"Hardware
Reference
Manual"
information.
SECTION
6:
DIP-SWITCH OPTIONS
for
remote
LEOs.
for
more
detailed
The
first
two
sections
of
DIP-Switch
S1
(51-1
and
S1-2)
select
the
basic
operating
mode
of
the
020Bug
Debugger/Diagnostic
package.
Switch
51-1
enables
or
disab1es
the
interactive
portion
of
020Bug.
If
S1-1
is
ON
(c10sed),
020Bug
enters
the
interactive
mode
on
power-up
or
reset.
This
is
the
normal
mode
for
using
020BUg.
If
51-1
is
OFF
(open),
020Bug
is
disabled.
and
the
system
will
switch
to
the
disk
operating
system
firmware
(if
present)
on
power-up
or
reset.
Switch
S1-2
enables
the
auto-self
test
mode
used
at
the
factory
f!),q~h
GMX
iNC
-3-
.
Rev.
A

for
testing
the
boards.
If
Sl-2
is
ON
(CLOSED),
the
board
enters
the
auto-se~ftest
mode
on
power-up
or
reset.
For
norma1
operation,Sl-2
shou1d
be
OFF
(OPEN).
disab1ing
the
auto-se1ftests.
See
Chapter
2
for
more
information
on
the
se1ftest
features.
Switches
Sl-3,
Sl-4.
and
Sl-5
may
be
used
by
the
option~
disk
operating
system
support
firmware.
Their
functions
are
described
in
the
OOS
documentation.
For
initia1
checkout.
set
the
DIP-Switch
as
shown
in
figure
6-1.
Recommended
Inittal
DIP-Switch
Settings
Sl
1 2 3 4 5
tJll0tJ0
1 =ON
2=OFF
3=
X
4=
X
5=
X
Figure
6-/
SECTION
7:
JUMPER
OPTIONS
020Bug
Enabled
Auto-selftest
D1sabled
See
DOS
OOcurnentation
See
DOS
OOcurnentation
See
DOS
ODJrnentation
The
GMX
Micro-20
is
shipped
with
most
of
the
jumper
options
properly
set.
Those
options
that
may
need
to
be
reconfigured
are
discussed
in
the
appropriate
sections
of
this
manual.
Refer
to
the
"Hardware
Reference
Manual"
for
detailed
information
on
jumper
functions.
Figure
'7-1
summarizes
the
standard
jumper
configuration.
Initial
Jumper
Configuration
Jumper
Configuration
JA-1A
As required by
EPROMs
used
JA-1B
Jumper
7 &
8.
9 & 10
JA-2
Jumper 1&2
JA-3
Jumper 1 & 2
JA-4
No
Jumper
..
JA-5
Jumper 3 &4
JA-6
As requtred by
EPROMs
used
JA-7
Jumper 1 &2,
3&4
JA-8
As required by
floppy
disk
drive
FIgure
7-/
~1986
GMX
INC
-4-
Rev
•.
A

SECTION
8:
FLOPPy
DISK DRIVES
This
section
covers
the
basic
requirements
for
floppy
disk
drives.
For
more
detailed
information
on
drive-requirements,
refer
to
the
operating
system
documentation.
8-1:
F10ppy
Disk
Drive
Requirements
In
order
to
use
one
of
the
optiona1
disk
operating
systems,
at
1east
one
f10ppy
disk
drive
must
be
connected
to
the
GMX
Micro-20.
The
board
supports
one
or
two
5
1/4"
floppy
disk
drives
and
most
standard
drives
can
be
used.
The
drives
must
be
capab1e
of
stepping
at
the
minimum
stepping
rate
defined
by
the
f10ppy
disk
contro11er
on
the
GMX
Micro-20
and
by
the
operating
system
software.
The
mimimum
stepping
rate
avai1ab1e
is
12
mil1iseconds/step.
Refer
to
the
operating
system
documentation
for
operating
system
defau1t
stepping
rates.
.
The
GMX
Micro-20
supports
any
combination
of
the
fo110wing
drive
formats:
sing1e
or
doub1e-density,
single
or
doub1e-sided,
and
48
or
96
TPI
(Tracks
Per
Inch).
The
format
(number
of
sides,
density,
etc.)
of
a
least
one
drive
(drive
#0)
must
match
the
format
of
the
suppli.'~.
operating
system
disks.
8-2:
Floppy
Disk
Drive
Configuration
Fo11ow
the
drive
manufacturers
instructions
when
programming
the
drives.
If
a
sing1e
floppy
disk
drive
is
used,
program
the
drive
as
Drive
#0.
If
two
drives
are
used,
program
the
first
as
Drive
#0,
and
the
second
as
Drive
#1.
If
on1y
one
drive
is
used,
it
must
have
its
terminating
resistor
(usual1y
a
resistor
pack)
in
place.
If
two
drives
are
used,
the
terminating
resistor
MUST
be
removed
from
one
of
the
drives.
Remove
the
terminator
from
the
drive
that
wil1
be
the
last
drive
on
the
cab1e
connecting
the
drives
to
the
board.
If
on1y
one
drive
is
used,
and
the
drive
has
a
head
load
s01enoid,
configure
the
drive
for
"head-10ad
with
drive
select"
operation.
If
two
drives
with
head-load
solenoids
are
used,
configure
both
for
"head-10ad
with
motor-on".
8-3:
Floppy
Disk
Ready
Option
Most
of
the
floppy
disk
drives
current1y
avai1ab1e
have
a
"drl
ready"
output
on
pin
34
of
the
interface
cab1e.·
This
output
is
as
a
signa1
that
the
drive
is
se1ected
and
ready
to
transfer
data.
(1)1986
GMX
INC
-5-
.
Rev.
A

If
the
drives
being
used
have
this
output,
the
Drive
Ready
Option
(JA-S)
on
the
GMX
Micro-20
..
should
be
enabled
by
jumpering
pins
1
and
2
of
JA-S.
If
one
or
both
drives
do
not
have
a
"ready"
output,
the
option
must
be
disabled
by
jumpering
pins
2
and
3
or
JA-S.
Note:
Some
older
drives
use
a
different
pin
for
their
"drive
ready"
output.
Ir
the
drive's
"ready"
output
is
not
on
pin
34
of
the
interface
cable,
the
Drive
Ready
Option
.must·be
disabI.ed.
8-4:
Floppy
Disk
Drive
Connections
Floppy
disk
interface
connector
P4
1s
used
to
connect
the
drive(s)
to
the
GMX
Micro-20.
The
pinout
or
this
connector
matches
the
industry
standard
drive
pinout,
and
a
standard
34-pin
ribbon
cable
can
be
used.
Be
sure
to
observe
proper
polarity
(pin
1)
when
connecting
the
drives
to
the
board.
Since
the
GMXMicro-20uses
the
same
power
supply
voltages
as
a
standard
5
1/4"
disk
drive,
both
can
be
powered
by
the
same
supply;
provided
that
the
supply's
current
limits
are
not
exceeded.
If
both
the
board
and
drive{s)
are
powered
by
the
same
supply,
separate
cables
to
the
power
supply
(rather
than
a
"daisy-chain"
arrangement)
should
be
used.
SECTION
9:
SASI INTERFACE
The
SASI
interface
1s
used
to
connect
intelligent
peripheral
controllers
(e.g.
hard
disk
controllers)
to
the
GMX
Micro-20.
The
type
of
controller
and
drive(s)
that
can
be
used
is
determined
by
the
disk
operating
system.
This
section
describes
the
basic
connected
to
the
SASI
interface.
Refer
documentation
for
specific
information
compatibility.
requirements
for·
devices
to
the
operating
system
on
controller
and
drive
9-1:
SASI
Controller
Requirements
The
controller(s)
used
must
be
compatible
with
both
the
hardware
and
the
operating
system
software.
Due
to
timing
restrictions,
some
or
the
available
devices
that
use
the
SASI
interface
are
not
compatible
with
the
GMX
Micro-20.
Unless
user
written
driver
software
is
used,
only
those
controllers
listed
in
the
operating
system
documentation
can
be
used.
At
the
time
of
this
writing,
the
only
SASI
controllers
that
have
been
tested
and
are
known
to
work
with
the
GMX
Micro-20
are
the
OMTI
20C-1
(OMTI,
Campbell
ca.)
and
the
XEBEC
1410
and
1410A
(XEBEC
SYSTEMS,
Inc.
Sunnyvale
ca.)
The
OMTI
5000
Series
controllers
are
NOT
compatible.
For
current
inrormation
on
controller
compatibilIty,
contact
GMX
Inc.
4)1986
GMX
INC
-6-
Rev.
'A
_ 1

9-2:
SASI
Contro~~er
Configuration
Refer
to
the
contro~~er
manufacturer's
documentation
when
configuring
SASI
controllers.
There
are
norma~~y
on~y
four
options
on
the
SASI
contro~~ers
which
must
be
configured
for
use
with
the
GMX·
M1cro-20:
contro~Ler
se~ect.
sector
size,
interface
termination,
and
parity
•
.
Contro~~er
se~ect
and
sector
size
must
be
set
according
to
the
information
in
the
operating
system
documentation.
If
on~y
one
SASI
contro~~er
is
to
be
connected,
it
must
have
its
terminating.
resistors
(usua~~y
a
resistor
pack)
insta~led.
If
more
than
one
contro~~er
is
connected,
the
terminators
must
be
removed
from
all
but
one
controller.
A
terminator
should
only
be
instal~ed
in
the
last
contro~ler
on
the
cable.
The
GMX
Micro-20
does
not
support
the
parity
option
on
the
SASI
data
bus;
parity
must
be
disab~ed
on
a~l
control~ers.
SASI
the
GMX
standard
used.
9-3:
SASI
Controller
Connections
interface
connector
PS
is
used
to
connect
the
drive{s)
to
Micro-20.
The
pinout
of
this
connector
matches
the
industry
controller
pinout,
and
a
standard
SO-pin
ribbon
cable
can
be
Be
sure
to
observe
proper
polarity
(pin
1)
when
connecting
the
controller(s)
to
the
board.
Most
SASI
controllers
use
the
same
power
supply
voltages
as
the
GMX
Micro-20,
and
they
may
use
the
same
power
supply:
provided
that
the
supply's
current
limits
are
not
exceeded.
If
one
supply
is
used,
separate
cables
to
the
power
supply
(rather
than
a
"daisy-chain"
arrangement)
'should
be
used.
SECTION
10:
PARALLEL
INTERFACE
The
printer.
a
device
device.
parallel
interface
is
normally
used
to
drive
a
parallel
This
section
describes
the
basic
requirements
for
connecting
with
a
Centronics
type
parallel
interrace
as
an
output
The
parallel
port
may
also
be
used
for
input,
aLthough
user
written
software
may
be
required
to
use
the
port
for
input.
10-1:
Parallel
Interface
Requirements
The
standard
driver
software
provided
by
GMX
Inc.
can
be
used
with
most
printers
that
have
a
standard
Centronics
type
parallel
interface.
01986
GMX
INC
-7-
-Rev.
A

10-2:
Para11e1
Interface
Configuration
Usua11y
no
special
configuration
is
required,
other
than
to
be
sure
that
the
printer
is
configured
for
para1le1
operation.
Some
printers
use
the
same
connector
for
para1lel
and
seria1
I/O
and,
if
connected
to
the
"para11el
port
while
in
the
seria1
mode,
could
damage
the
GMX
Hicro-20.
10-3:
Parallel
Int~rface
Option
Jumpers
Two
jumper
areas
(JA-3
and
JA-7>
select
the
data
and
handshake
direction
for
the
paralle1
interrace.
Both
jumper
areas
must
be
set
for
output
when
the
port
is
used
to
drive
a
printer.
To
configure
the
port
for
output,
jumper
JA-3
pins
1
and
2,
jumper
JA-7
pins
1
and
2,
and
jumper
JA-7
pins
3
and
4.
~1986
GMX
INC
-8-
Rev.
A

CHAPTER
2
SYSTEM
CHECKOUT
This
chapter
covers
the
procedures
for
initial
system
checkout.
It
includes
information
on
the
built-in
confidence
tests
and
hardware
diagnostics.
SECTION
11:
HARDWARE
DIAGNOSTICS
11-1:
Initial
Power-up
Test
With
the
console
terminal
connected,
and
the
DIP-switch
described
in
Chapter
1,
apply
power
to
the
GMX
l1icro-20.'
The
LED
should
come ON.
then
go
OFF,
and
the
020Bug
sign-on
message
appear
on
the
terminal,
followed
by
the
prompt:
020Bug>
set
as
status
shoul.d
If
the
020Bug
sign-on
message
and
prompt
do
not
appear.
check
the
Halt
(LEDl)
and
status
(LED2)
LEOs.
If
neither
is
lit,
the
problem
is
probably
in
the
power
supply,
the
terminal
configuration,
or
the
connections
to
the
terminal.
Recheck
the
connections
to
the
board
and
the
terminal
configuration.
If
the
diagnostic
LED
(LED2)
is
flashing.
the
power-up
confidence
tests
have
detected
an
error
condition.
Refer
to
the
section
on
confidence
tests
for
more
information.
If
the
Halt
LED
is
lit,
the
processor
has
halted
due
to
a
system
fault.
This
may
be
caused
by
incorrect
installation
of
the
PROMs
(be
sure
the
PROMs
are
installed
in
the
correct
sockets),
a
short
on
the
board
(check
around
the
board
mounting
screws
if
the
board
is
mounted
on
a
drive
or
cabinet),
or
a
hardware
failure.
Refer
to
the
hardware
manual
for
more
information
on
the
hal.t
condition.
Once
the
prompt
is
obtained,
020Bug
is
ready
to
accept
commands
from
the
console.
The
next
step
should
be
to
run
the
020Bug
Diagnostics
to
verify
that
the
board
is
functioning
properly.
11-2:
Confidence
Tests
The
Support
ROM
firmware
incl.udes
a
group
of
tests
that
check
basic
functions
of
the
board.
These
tests
are
al.ways
run
at
power-up
or
reset,
regardless
of
the
mode
selected
by
the
DIP-Switches.
In
order
to
provide
a
faul.t
indication,
even
if
the
fault
prevents
normal
communication
through
the
console
terminal,
the
confidence
tests
use
the
Status
LED (LED
2)
to
signal
the
fault
.
through
a
series
of
coded
fl.ashes.
<U>1986
GMX
INC
-9-
.
Rev.
A

If
one
of
the
confidence
tests
fa·i~s,
a
4-bit
code
is
"f~ashedtt
to
indicate
the
nature
of
the
fau~t.
The
code
is
transmitted
most-significant
bit
first
in
the
fo~~owing
form:
A
series
of
short
f~ashes
equa~s
a
zero
(0)
A
steady
"ON"
equa~s
a
one
(1)
A
short
off
period
separates
individu~
"bits"
in
the
message.
The
message
repeats
cont1nuous~y,
with
a
~onger
off
period
separating
1ndividua~
messages.
For
examp~e!
F~ash
-
Steady
-
F~ash
-
F~ash
-
Long
Pause
•••
(repeat)
trans~ates
to
0100
binary.
their
descriptions.
Figure
11-1
~ists
the
error
codes
and
Note:
LED
2
is
connected
to
the
f~oppy
disk
contro~~er
side
se~ect
~ine
and
wi~~
a~so
f~ash
during
norm~
disk
operation.
The
confidence
tests
are
run
immediate~y
after
power-up
or
reset
and
this
is
the
on~y
time
the
error
codes
are
valid.
CONFIDENCE
TEST
ERROR CODES
CODE
ERROR DESCRIPTION
0000
Not used
0001
68020
Register
Error
0010
68020
Instruction
Error
0011 Reset
Failure
0100
PROM
Checksum
Error
0101 Addressing
Mode
Error
0110
Exception Failed To Occur
0111 Wrong Exception Generated
1000
Status
Register
Interrupt
Bit
Stuck
1001 Unexpected
Interrupt
1010 Memory
Error
101
1 Unexpected Bus
Error
1100
Serial
Qevtce
(QUART)
Error
1101 Reserved
for
future
use
\!\~
~r\.MWIIlt
I!AM'\
II
1110 Reserved
for
future
use
Ul\v~
cM'lfJ
",,;J;}~tJ
"-
1111 Reserved
for
future
use
Figure
//-/
<H
986
Gl1X
INC
-10-
Rev.
A

11-3:
020Bug
Diagnostics
In
addition
to
the
confidence
tests,
which
are
always
run
at
power-up
or
reset,
020Bug
includes
a
set
of
hardware
diagnostic
commands
that
check
various
board
functions.
These
diagnostics
can
be
executed
as
commands
from
020Bug,
or
automatically
if
the
Auto-self
test
is
enabled
(Sl-2,
ON).
The
diagnostics
should
be
run
during
initial
checkout,
and any
time
a
hardware
problem
is
suspected.
The
diagnostics
can
be
run
individually,
or
as
a
group.
The
following
command
sequence
will
run
all
of
the
diagnostics.
Refer
to
the
"020Bug
User's
Manual"
for
a
description
of
the
individual
tests.
To
run
the
020Bug
diagnostics,
enter
the
following
commands
«cr>
=
carriage
return):
SD<cr>
020Bug
should
respond
with
the
diagnostic
directory
prompt:
M20Diag>
Then
enter
the
self-test
command:
ST<cr>
As
each
test
is
run,
020Bug
will
print
the
name
of
the
test,
followed
by
a
pass/fail
message.
When
all
of
the
tests
are
completed
successfully,
the
diagnostic
prompt
is
again
displayed.
11-4:
Self
test
Loop
Mode
The
Self
test
Loop
Mode
provides
a
means
of
repeatedly
executing
the
020Bug
self
test
commands
without
operator
intervention.
This
mode
runs
the
same
tests
as
the
020Bug
"STU
command,
but
in
a
slightly
different
way.
In
the
Self
test
Loop
Mode
the
tests
run
in
a
loop,
repeating
until
an
error
occurs
or
the
test
is
stopped.
If
an
error
is
detected
the
status
LED (LED
2)
begins
flashing
to
indicate
that
an
error
has
occurred.
Unlike
the
confidence
tests,
the
status
LED
does
not
indicate
the
nature
of
the
error,
but
simply
that
an
error
has
occurred.
The
normal
self
test
error
reporting
(on
the
console
terminal)
does
however
indicate
what
error
has-
been
detected.
The
Self
test
Loop
Mode
can
be
entered
in
one
of
two
ways.
The
command
"STL<cr>"
in
the
020Bug
diagnostic
directory
will
initiate
this
mode
of
operation.
Once
started.
the
tests
will
run
until
an
error
occurs
or
the
test
is
stopped
with
the
"break"
key
or
by
a
reset.
If
Self
test
restore
reset
or
DIP-Switch
Sl-2
is
place
in
the
ON
(closed)
position,
the
Loop
Mode
is
entered
automatically
on
power-up
or
reset.
To
normal
operation,
return
51-2
to
the
OFF
(open)
position
and
power-down
the
board.
~1986
GMX
INC
-11-
Rev.
A


GMX
Micro-20
DC
Power
Connector
P8
1 2 3 4
,'
..
'
/,
......
,,/,'
--/.////%//~/.
////
~
/~
"~
'/
/~r'/'
/)
..
1
..
-
~;'/'>~'
//~
Component
Side
+12VDC
~
Regulated I
GND
'---
__
+5
VDC
Regulated
(4.5
Amp
Max"
Note:
Current
requirements
for
the
+ 12
Volt
DC
supply depend
on
the
serial
adapter board used.
Appendix A
Table of contents