PacComm TINY-2 - Page 141

TROUBLESHOOTING
Computer
Terminal
interrace
Packet
controller
won’t
sign
on
to
the
computer.
if
you
find
the
TINY-2/MICRO-2
won't
send
data
to
the
computer,
but
appears
to
operate
properly
as
described
in
General
Tests
above,
verify
that
the
CTS
line
at
RS-232
connector
P4
pin
8
or
TTL
connector
P3
pin
4
is
not
being
held
low.
The
packet
controller
will
not
send
data
to
the
computer
unless
its
CTS
line
is
asserted.
If
the
computer
does
not
implement
the
RTS/CTS
protocol,
the
RTS/CTS
lines
(pins
7
and
8
on
P4)
should
remain
unconnected
to
the
computer
or
else
tied
together.
Check
the
baud
rates
set
on
the
packet
controller
and
computer
terminal.
Some
mismatched
combinations
of
baud
rate
on
controller
and
terminal
will
cause
nothing
to
be
displayed.
If
the
above
checks
are
ok,
observe
pin
26
of
the
SIO
(U14)
with
an
oscilloscope
and
cycle
the
packet
controller
power
switch.
Transitions
on
this
pin
shortly
after
reset
indicate
that
the
packet
controller
is
sending
data.
If
no
signal
transitions
are
seen,
recheck
that
the
CPU
appears
to
be
operating
(see
below.)
If
data
appears
to
be
present,
verify
that
TTL
transitions
are
also
present
on
the
Max
231
(U15)
pin
8
and
RS-232
signal
transitions
are
present
on
Max
231
(U15)
pin
11
and
P2
pin
2.
The
controller
prints
only
gibberish.
This
indicates
that
some
combination
of
the
data
rate
(terminal
baud
rate),
parity
option,
or
number
of
start
and
stop
bits
are
not
set
the
same
at
the
packet
controller
and
at
the
computer
terminal.
Verify
that
the
computer
terminal
is
set
for
eight
data
bits,
no
parity,
and
1
stop
bit.
These
settings
may
be
made
with
DIP
switches,
jumper
pins,
or
software
commands
depending
on
the
computer
terminal
in
use.
The
above
settings
are
the
default
sign-on
settings
stored
in
the
TINY-
2/MICRO-2
EPROM.
Perform
a
hard
reset
by
pressing
the
power
switch
OFF
then
ON
(outthenin).
The
sign
on
message
should
appear.
If
the
packet
controller's
sign-on
message
lines
appear
to
be
typed
over
each
other,
you
should
set
the
packet
controller
command
AUTOLF
ON.
if
the
sign-on
message
appears
to
be
double-spaced,
you
should
set
AUTOLF
OFF.
If
the.
sign-on
message
appears
to
be
single-spaced,
AUTOLF
Is
correct.
:
The
controller
won’t
accept
commands.
20
After
the
packet
controller
signs
on,
try
giving
it
any
command.
If
the
default
settings
are
in
effect,
it
will
attempt
to
echo
each
character
you
type
back
to
the
screen.
if
it
doesn’t
echo,
be
sure
that
the
SIO
(U14)
pin
23
has
a
voltage
level
between
0
and
+0.4
volts
on
it.
The
voltage
on
Max
231
pin
5
should
be
greater
than
+3
volts.
If
these
conditions
are
not
met,
check
the
cable
wiring
and
refer
to
the
section
about
terminal
interface
troubleshooting.
If
the
above
checks
are
OK,
use
an
oscilloscope
to
verify
that
data
is
present
on
SIO
(U14)
pin
28
and
Max
231
(U15)
pin
10
when
you
strike
a
key'on
the
computer.
If
not,
the
data
isn’t
getting
from
the
computer
to
the
packet
controller.
Check
the
serial
connector
in
use
(P4-RS-232,
TINY-2/MICRO-2
Technical
Ret.,
2
Ed
©
1989,
PacComm,
Inc.