Radio Shack TRS-80 Service Manual page 57
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- Reference manual (274 pages) ,
- User manual (236 pages) ,
- Service manual (199 pages)
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APPENDIX
B
SIGNAL
GLOSSARY
ELECTRONIC
BOARD
This
signal
listing
is
keyed
directly to
the
printer
schematic
No.
6379105-9001.
All
signal
mnemonics
contained
on
this
drawing
are
listed
alphabetically
with
their
source
and
destinations.
The
notation
(N) after
a signal
mnemonic
is
used
to
indicate
the "not"
or
inverse function
of
the
signal.
For
example, CIP
(N)
is
the "not" function
of
the CIP
signal.
The
(N)
notation
is
equivalent
to
the bar
appearing over
a signal
as
shown
on
the
schematic.
The
following
method
is
used
to identify
the
signal
source
and
destination
locations:
ME3-9
signifies
element
pin
9.
SIGNAL
GLOSSARY
SIGNAL
NAME
ACK(N)
BUSY
CARRY(N)
CG1(N)-
CG7(N)
CIP
CIP(N)
CIR(N)
DATA
1 -
DATA
7
DCCR(N)
DCLF(N)
DSTA(N)
EOPPRM(N)
EOPSW
LBUSY(N)
LEDEOP
DESCRIPTION
Printer
acknowledge
pulse
indicating
the input
completion
of a
character
into
memory
or
the
end
of a
functional operation.
Printer
busy
status
line
to input
device
indicating that
printer
is
not
ready
to
receive
data.
Signal
used
to
indicate
reception
of a
full
132
character
line of
data
and
to
generate
print
command.
Signals
used
to
energize the
print
head
solenoids.
Carriage
in
Print
—
Signal
used
to drive
the
print
head
forward.
Inverse
of
CIP
Carriage
in
Reverse
—
Signal
used
to
drive
the
print
head
in
reverse.
The seven
data
lines
coming
from
the
input
via
input
connector
to
the
printer.
Decoded
carriage return
Decoded
line
feed
The
data strobe signal
from
the
interface
connector
used as an
input
clock.
End
of print
prime
signal
used
to
clear
print
control
logic.
End
of print
switch
An
immediate
60
ms
Busy
condition
caused
by
a
CARRY(N)
or
DCLFCIP(N)
Limits current
to
the
light
emitting diode
in
the
EOP
switch.
SOURCE
ME6-6
ME6-11
DESTINATION
J001-10
J001-11
ME2-11
ME24-1,
2
ME20-12
J002-
PRINT
HEAD
ME3-9
ME10-3
J002-4
ME10-6,
ME12-10
J002-J
Forward
Carriage
Solenoid.
J001-2
Thru
—
ME23-8
ME22-5,
ME6-10
ME3-4
ME17-8
ME12-9
ME2-4
E3
J001-1
ME10-8
ME22-13
ME9-9
ME5-3
ME5-4
J003-12
ME11-13
ME2-9
ME5-12
J003-6
LED
in
the
EOP
switch.
B-1
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